Housing, management, and breeding practices for ferrets are in many ways like those of other carnivores, and the principles discussed in this chapter can frequently be applied to the cat.
A Historical Perspective
Ferrets in England were maintained for rabbit hunting as well as ferreting for rats. As such, early literature exists on management practices of the domesticated ferret in the early 1900s [1]. Hutches raised from the ground were often kept in an open shed or outbuilding with adequate air circulation. The legs supporting the cage were recessed to prevent them from being excessively contaminated with excreta during cleaning. The wooden hutch had a lid over each compartment; the nesting area had a wire grid top for better air circulation (Fig. 6.1). Outdoor hutches had slanted roofs made of board. The floors were made of galvanized wire netting for ease of cleaning. Loose solid boards were often placed on the wire grid floor and, when soiled, removed and cleaned. One portion of the wire flooring, far from the nesting area, was left uncovered to be used for urination and defecation. The exterior of the cage where excrement fell through was protected by a galvanized iron or zinc sheet to protect the wood of the cage. The finely sifted dirt below this area served as the litter box and the contaminated soil was removed daily, with fresh soil added as necessary. Wounded or sick ferrets were maintained in separate hutches. Authors stressed that with this type of caging, the ferret's nails needed to be trimmed on a routine basis.
Fig. 6.1. Wooden hutch. Modified from Hovell, M (1924) Rats and how to destroy them. London: John Bale, Sons & Danielson Ltd.
The nest compartment was provided with clean wheat straw and changed once a week. Before the fresh straw was added, the floor was cleaned and sprinkled with a nonpoisonous germicidal disinfectant [1].
Feeding dishes were made of either galvanized or enameled iron. A drinking fountain, the water container type used for poultry, ensured a fresh supply of water. A stoneware fountain was used, preferentially because it was easier to clean than those made of zinc or galvanized iron. The water container was sterilized by boiling in water for a few minutes. Ferrets were maintained primarily on fresh meat of small animals such as mice, rats, and birds. Bread and milk were often given as a supplement once or twice a week. Sick ferrets received a mixture of raw meat and milk or an uncooked fresh chicken egg.
Individuals who raised ferrets for hunting stressed the importance of constantly handling the ferrets in order to tame them. In some households, children were evidently allowed to play with the ferrets in escape-proof areas, where long drain pipes substituted for rat tunnels. This playing allowed the ferret to be handled frequently and accustomed the ferret to be unafraid of exiting from the authentic rat holes during actual rat hunting forays.
Ferrets were not handled by picking them up by their tails or by holding the head. They were restrained by holding firmly without undue pressure around the shoulders, with the front feet protruding from beneath the attendant's fingers. Often, gloves were not used when restraining ferrets.
Housing in Breeding Farms
Cages patterned on mink breeding operations have commonly been used for ferret breeding farms (Fig. 6.2). These cages are typically suspended with wire bottoms to facilitate cleaning. Unfortunately, ferret excreta may not drop through the wire as it tends to be moist and is extruded in piles which stick to the wire. The ferret often backs up against the wall of the cage to defecate, creating rather large fecal piles that do not fall through, despite the wire bottom, and require scraping out regularly—if not daily—to maintain adequate sanitation. Ferrets are very social, except when a male is in breeding condition. Ferrets, therefore, take readily to group housing.
Fig. 6.2. Whelping cage setup in breeding facility.
Housing in a Research Setting
A number of factors need to be considered in regard to safe and adequate housing for the ferret. Many of the same principles used to house ferrets 100 years ago are still in use today, with differences being primarily in the materials used to construct cages and the availability of defined diet formulations.
Physical Facilities and Environment
Under proper environmental conditions, the ferret can be housed indoors or outdoors.
Temperature and Humidity
Although ferrets can be maintained outdoors at temperatures as low as 7–10°C (45–50°F), and for experimental purposes in a refrigerated room, low temperature and high humidity should be avoided [2]. Similarly, elevated temperatures, above 30°C (86°F), cannot be tolerated; because of poorly developed sweat glands, the ferret is susceptible to heat prostration. Clinical signs of hyperthermia include open-mouthed breathing, panting, eventual flaccidity, and occasional vomiting. Particular care must be exercised when transporting ferrets in poorly ventilated vehicles. Temperatures for the ferret appear to be 14–18°C (57–65°F), with a humidity range of 40–65%; unweaned ferrets should be maintained at a minimum temperature of 15°C (59°F). The optimum temperature range recommended by the Council of Europe Convention for ferrets is 15–21°C (59–70°F) [3]. In our experience, ferret kits are maintained at 68–70°F without ill effects. This chapter contains additional information on European regulations for ferret housing and husbandry.
Lighting
Lighting is set at 12 : 12 light : dark cycle in conventional housing to maintain stock animals. Light can be manipulated to control breeding cycles. Ferrets are seasonal breeders and, by increasing daylight or by exposure to longer periods of artificial light when housed indoors, estrus can be induced in females, and sexual activity can be stimulated in immature males (see Chapter 8).
Air Handling
Like most laboratory animals, ferrets utilized for biomedical research should be kept in rooms with 10 to 15 air exchanges of nonrecirculated air per hour [4]. This is particularly important in ferret husbandry because of their musky odor, and for disease prevention because of their susceptibility to respiratory viral infections. In addition, efforts should be made to minimize transmission of the ferret's strong odor to rodents maintained in the same vivarium. The rodent's fear of ferrets (stimulated by olfactory senses) can cause any trace of ferret scent to interrupt breeding cycles or disturb other physiologic processes.
Caging
Various primary enclosures have been described to house ferrets. Most of them consist of metal rod framework, similar to the design used to house rabbits and cats (Fig. 6.3). The flooring may be solid or consist of metal cross braces, allowing urine and some feces to collect in a drop pan. The size of spacing in grid walls should be 1.0 × 0.5 in. and 0.25 in. if using wire mesh or slatted flooring. If small numbers of ferrets are maintained in a vivarium, rabbit cages can be modified to house ferrets. A specially made wire grid can be secured to the front of the cage to prevent escape. A European made, commercially available cage originally used to house guinea pigs is also available for ferrets (E. Becker & Co., Castrop-Rauxel, Germany). It consists of a large plastic box with solid floor (810 mm wide, 610 mm deep, 250 mm high) [5]. Caging standards for the ferret were not specified in the eighth edition of the National Institutes of Health (NIH) Guide [4], but the size described by Wilson [6], 49 × 46 × 46 cm, meets the space requirements cited by the Royal Society of England [3]. Minimum space requirements for housing ferrets have been published for the United Kingdom and Europe.
Ferrets prefer a small enclosure as a nesting area; if paper or cardboard sheets are used as contact bedding, they are often found nestled beneath them. A solid-bottomed plastic rodent cage can be modified to serve as a nesting area [7]. A customized nest box has also been used successfully in Massachusetts Institute of Technology (MIT) ferret colonies.
Solid plastic caging can also be used to house ferrets. One cage described measures 37 × 24 × 25 cm, with the bottom covered with sawdust to facilitate cleaning [3]. It is suggested, however, that this type of cage be used only for short-term housing. Solid-bottomed rodent caging for weanling ferrets has been successfully used and is particularly useful for maintaining their body temperature.
Because of ferrets' tendency to lick and bite their enclosures, careful attention should be given to monitoring ferrets for trauma to the teeth and gums. Zinc toxicity has been noted, caused by ferrets licking zinc compounds from the galvanized bars of the caging, leached from the metal as a result of steam sterilization (82°C for 20 minutes; see Chapter 5) [8].
Molded plastic caging used to house rabbits is also appropriate to house ferrets (Fig. 6.4). It has a solid bottom perforated with holes, a wire slat front, and slatted plastic sides. The floor provides a pliable and easily sanitizable surface. Ferrets are less likely to lodge their feet in this type of flooring than slatted stainless steel flooring often employed in rabbit cages. Use of cage board as contact bedding is also recommended.
Fig. 6.4. Plastic rabbit cage with stainless steel front used to house ferrets.
Ferrets may be housed singly or in groups by sex. If sufficient space is available and maximum breeding efficiency is essential, estrous females should not be housed together, nor should females that have been mated, because of sexual play eliciting ovulation or pseudopregnancy [9]. However, the risk of pseudopregnancy may not be worth the disadvantages of single housing: jills thrive when maintained together. Also, in group housing, sexually active males should be removed because of their tendency to fight.
Ferrets can be trained to use a litter box placed in a cage. Nonscented clay cat litter, pine shavings, or pelleted litter material may be used. One author has cautioned that clay litters may lead to chronic upper respiratory irritation from inhaled dust or to a dry, brittle haircoat from digging and playing in the litter [10].
An enclosed sleeping area with appropriate bedding should be provided for ferrets. If it is of sufficient size, it can also be used as a nesting box (Fig. 6.5A,B). Towels, cage board, hammocks, or our favorite, snooze tubes made of easily washable material, are also provided for the well-being of the ferrets (Fig. 6.6).
Fig. 6.5. (A and B) Nesting box.Fig. 6.6. Snooze tube—a favorite location for sleeping ferrets.
Ferrets are tunnel dwellers in nature so they very much appreciate tubes and tunnels. They are very playful and active at certain periods of the day but will sleep profoundly for hours at other times—so much so that they may be difficult to rouse and even appear dead. Young kits, especially, are full of energy and curiosity. They do best when housed together and are also regularly handled by people so that they grow up socialized to other ferrets and personnel caring for the ferrets. Ferrets can be housed in smaller cages that accommodate a litter, but the litters may be grouped for playtime in a larger container with toys such as translucent tubes, balls, chew toys, and pans of water in which they love to jump and splash. Large, dark, Rubbermaid-type tubs may be hooked together with tubes and modified to provide feeders and waterers, allowing ferrets to move from tub to tub, mimicking their normal subterranean habitat [11]. Dark tubing or nest enclosures may interfere with exposure to a light cycle when the animals are being prepared for breeding. Recently weaned ferrets, however, will take advantage of such accommodations. Many pet and research ferrets are provided hammocks. However, on occasion, enrichment devices may also become agents of destruction and so should be employed with care. In a research setting, as is the case for pet ferrets, socialization is important, and designated play time allowing ferrets to interact with each other is strongly encouraged (Fig. 6.7).
Fig. 6.7. Ferrets at play. Social interaction is an important component of ferret husbandry.
Appropriate care is necessary when selecting toys for ferrets. They like to bite off portions of rubber or plastic toys, potentially resulting in gastrointestinal obstructions. Use of polyvinyl chloride (PVC) piping for a ferret to tunnel through provides an attractive pastime in the daily routine and promotes health by encouraging exercise [10].
Another housing strategy which can easily be made to meet EU size standards and can readily be used in many research settings is to create ferret corrals by using sanitizable heat-/chemical-resistant panels that can be assembled with snaps or hinges (mounted preferably on the exterior of the corral). The walls can be used for adjacent pens. The height needs to be at least 2 ft. If the enclosure is filled with bedding, the ferret may tunnel happily in this environment and build nests with the addition of some aspen shred or excelsior material. This style of housing is simple and effective but may not allow for the most efficient ferret density in a room. The other drawback is that the excreta must be removed by long handled brushes and scoops daily, with the entire room and panels being disassembled and thoroughly sanitized at least every other week.
Housing for SPF Ferrets Used for Influenza Research
To raise large numbers of specific pathogen free (SPF) ferrets, especially for influenza work, it is desirable to have separate facilities or at least different rooms that can be handled by dedicated personnel. Should a staff member inadvertently introduce influenza into a portion of the colony, the entire effort will then not be compromised. Influenza spreads explosively through a naïve ferret breeding operation, which will then be compromised for over a year—until the kits born of the infected dams themselves reach breeding age, since the offspring of infected dams will be passively serologically positive until they are at least 3–5 months of age and their titers have then declined to below the level of detection. Offspring from these kits will once again be truly naïve. The SPF colony should therefore ideally have several different rooms under negative air pressure with respect to a central corridor. The rooms may have the light cycles adjusted for when the animals need to be rested in the dark cycle (8 hours light, 16 hours dark) or jills brought into estrus or hobs into breeding condition when the cycle will be reversed (16 hours light, 8 hours dark). Additional rooms may be used to house ladies in waiting, whelping jills, and weanling kits.
To maintain an SPF colony of ferrets, the usual barrier considerations apply: entry locks, sterilization/decontamination procedures for equipment and supplies, structural/heating, ventilation, and air conditioning (HVAC) integrity, and a closed colony. However, beyond the usual strict requirements for successfully producing and maintaining a defined health status in research animal breeding colonies, the ferret's susceptibility to influenza requires special housing considerations. Being exquisitely susceptible to all human influenza strains renders it the most suitable laboratory animal for influenza research (see also Chapter 25); however, it also makes it extremely difficult to raise ferrets without exposure to influenza, a common human infection that occurs annually even in previously infected individuals. While vaccination can certainly reduce the likelihood of the animal technician becoming infected and spreading the virus to ferrets, vaccines are not entirely protective, and influenza strains may be in circulation that are not included in the strains selected by the Centers for Disease Control and Prevention (CDC) for the annual allocation of influenza vaccine. Influenza virus is also highly contagious by aerosol or fomites, though it is fairly easy to inactivate with most common sanitizing agents such as 10% bleach and 70% alcohol. Therefore, the key to successfully raising influenza-free ferrets is the need to have strict personnel entry procedures in place, and vigilance of personnel working with influenza-naïve ferrets is required at all times. Staff may wear high-efficiency particulate absorption (HEPA)-filtered hoods that are more comfortable to wear, since they deliver a steady stream of cool air as opposed to a surgical mask or respirator-style mask, which are very difficult for personnel to use properly (Fig. 6.8). Invariably, personnel will pull the mask down so as to breathe more freely, and thus contaminate their hands/gloves with respiratory secretions. The HEPA-filtered hood, however, must not only deliver clean air but also function to filter the exhaled air before it returns to the room. Stryker surgical helmets (Stryker, Kalamazoo, MI, USA) used to protect the surgeon from a patient's blood and spray during orthopedic procedures, while also protecting the patient and the open wound from the surgeon, can be used for this purpose. The filtration of exhaled air occurs through the disposable fabric of the hood which must be tucked into the garment and have a loose seal at the neck. Less expensive versions of this style hood/helmet are now available and should accomplish the same purpose—protecting the animal from the technician while also providing a comfortable environment for the technician while working in the animal room. Unfortunately, all the protective equipment and well-thought out procedures will not guarantee success unless the staff fully understands and appreciates infection control processes—which can be exceedingly difficult when influenza is so common and may easily be mistaken for a cold or an allergy. Also, technicians may themselves be unaware they are shedding virus in the early phases of infection or may contract the virus from family members—especially young children—and may be a source of contamination to the colony. Personnel must not return to work until they are fully recovered.
Fig. 6.8. Staff personal protective equipment (PPE)—Stryker surgical helmet used in influenza research.
When ferrets are introduced into the research facility for infectious disease studies such as influenza studies, they may be housed in individually ventilated caging (IVC) to help protect them from infected employees at the research facility (Fig. 6.9 and Fig. 6.10). It is typically unnecessary to have the research staff then wear HEPA-filtered hoods. Using surgical masks is still highly recommended. When working with IVC, following standard protocol is necessary; that is, cage changing or animal handling is performed only in biological safety cabinets (BSCs) or HEPA-filtered husbandry work stations.
Fig. 6.9. IVC (Techniplast Double Decker rat cage modified for ferrets).Fig. 6.10. IVC and ferret.
Housing of Pet Ferrets
Ferrets are increasingly popular as pets. It is important for prospective ferret owners to consider the complexity of having a pet ferret because of its behavioral traits and specialized husbandry needs. Impulsive buying of ferrets is discouraged. It has been estimated that there are 5 million ferrets as household pets in the United States; the United Kingdom has >100,000; Germany 115,000; Italy 105,000; and France 300,000 pet ferrets [12]. Ferrets are also becoming popular as pets in Japan. It is important when considering housing needs and animal well-being that basic considerations of the ferret's temperament be considered. Ferrets have an inherent need to explore, have a need to have a secure resting area, as well as ample opportunity to play.
Ferrets can be housed both indoors as well as outdoors, provided adequate shelter is provided in inclement weather and shade during the summer months. Elaborate outdoor ferret areas are also described [11]. Cage sizes for pet ferrets vary, but in one citation, the minimum cage size for one to two ferrets is at least 1.5–2 m2 [13]. In an enrichment study on ferrets, the authors found increased overall health (body weight and fur quality) in those ferrets with increased floor space allowance, interaction with other ferrets, and access to toys [14]. Most ferret owners prefer larger enclosures if practical. An aquarium is not recommended due to poor air circulation. Choice of bedding varies from straw to heat-treated wood shavings that do not create dusty aerosolized material. Owners prefer torn-up blankets, towels, or sheets [11].
Ferrets can be trained to use litter boxes, but they can also mark their territories whether in the primary cage or their immediate surroundings. Behavioral problems, such as aggression, fearfulness, urinating, and defecating out of the litter box, and destructive behavior can be minimized when attention is focused on basic husbandry needs. An adequate and secure resting place is necessary, particularly as it has been reported that ferrets can sleep for 18–20 h/day [15]. Others consider 12–16 hours of sleep daily as normal for ferrets. The ferret snooze tubes are a favorite of ferrets during sleep or resting (Fig. 6.6). Activity of the ferrets is routinely governed by the household daily routine [15]. Plastic tubes in the ferret's environment are often used to allow pet ferrets to play and hide. More elaborate tubing designs can be used to mimic natural den constructions, for example, rabbit burrows (Fig. 6.11). Daily handling of pet and research ferrets is advised to socialize the animals to household members or laboratory personnel and to reduce aggressive behavior.
Play behavior is readily observed in ferrets, particularly in juvenile ferrets (6–14 weeks of age) but can continue to adulthood. This consists of rapid playful movements, play fighting with cagemates, manipulating objects, and chasing artificial prey [15,16]. Providing sufficient enrichment devices and toys enhance play behavior. Toys should be selected with caution because ingesting plastic or rubber toys can result in obstructions of the gastrointestinal tract.
Food and Water
Nutritional needs and dietary habits of the ferret are addressed separately (see Chapter 5). In regard to husbandry, however, a selected number of dietary issues will be mentioned here.
Food
Ferrets are carnivores and have historically been fed a diet of meat or meat by-products. Due to the large body of literature available on the nutritional requirements of another commercially reared mustelid, the mink, many recommendations about the ferret's dietary needs are extrapolated from those cited for the mink. Feral ferrets are known to survive on various small mammals, particularly mice. One laboratory in England, which has used ferrets extensively for physiology and anatomy studies, has successfully maintained their ferrets on dead mice and rats [3,11]. Feeding these protein sources is still recommended for pet ferrets in some countries. Use of frozen rats and mice poses a risk of Salmonella (and potentially other pathogens). A recent report indicates that frozen rodents used by owners of pet snakes have resulted in salmonellosis in household members [17]. In many research settings, however, and with most household pet ferrets, such a diet is neither practical nor appealing. The use of raw chicken, beef, horsemeat, or their by-products is discouraged for research and pet ferrets because of the likelihood of Campylobacter spp., Salmonella spp., Listeria spp., Mycobacterium spp., Clostridium spp., and Streptococcus spp. contamination (see Chapter 14). Most ferrets are therefore fed a commercially available cat or ferret food, both in the canned moist form and the pelleted form (see Chapter 5). There have been numerous recalls in commercial brands of pet food containing Salmonella, necessitating scrutiny of the commercial brand of food fed to ferrets [18]. We have successfully maintained a nonbreeding research colony (average daily census, 50–150 animals) for 8 years on pelleted cat food supplemented with various canned cat food products. Similar results have been obtained by others who have used pelleted mink chow. Currently, the use of commercial, pelleted ferret food, supplemented with canned kitten food is used in the MIT ferret colony. However, ferrets are not accustomed to eating fish by-products, and canned food with fish products is not recommended. It is generally believed that adult ferrets need a diet consisting of 30–40% meat-based protein and approximately 18–30% fat, with the remainder of the diet correspondingly low in carbohydrates and fiber (see Chapter 5).
A ferret usually consumes 140–190 g of semimoist food daily. On a dry weight basis, daily food consumption for male and female ferrets is 43 g/kg body weight [19]. Mean food passage time as measured by a dye marker in the feed is 182 minutes, reflecting a relatively short digestive tract. Ferrets with free access to food will eat 9 or 10 meals a day [20]. Care should be exercised to ensure that ferrets, especially males, do not become obese; restricted food intake is recommended. Since pet ferrets are prone to developing gastric trichobezoars, a feline hairball laxative (1–2 mL every 48–72 hours or as needed) is sometimes recommended [10]. Ferret laxatives are also now available (Laxatone® for Ferrets, Tomlyn, Princeville, Quebec, Canada; 1/4–1/2 tsp for 2–3 days, then 1/4 tsp 2 to 3 times a week).
Water
Potable fresh water should be available ad libitum. This is supplied either in stainless steel water bowls or in water bottles equipped with stainless steel sipper tubes. When using a pelleted diet, mixing the diet with water not only provides another source of water but, in our experience, also makes this form of diet more palatable for the ferret (Fig. 6.12). In the study by Andrews and Illman, water intake was noted for adult male ferrets to be 39 ± 6 mL/day, and for adult females at 17 ± 2 mL/day; according to the authors, however, the ferret readily consumes milk, and the low water intake was a result of supplementing these animals with milk [3]. Average daily water intake in adult ferrets is estimated at 75–100 mL [21]. Historically, bread and milk was sometimes fed regularly, but authors noted that this diet predisposes the ferret to periodontal disease and diarrhea [22].
Fig. 6.12. Ferret eating pelleted cat diet mixed with water.
Sanitation
Food and water bowls should be changed daily. If water bottles with stainless steel sipper tubes are used, they should be replaced with clean sanitized bottles two or three times weekly.
Because of the musky odor produced by the sebaceous and anal glands, in addition to the constant need to minimize microbial cross contamination, caging should be routinely sanitized with appropriate disinfectants or with 180°F water that can destroy vegetative microorganisms. In a research setting, this is accomplished by sanitizing the caging at least weekly; if using suspended grid flooring, the drop pans, preferably constructed of stainless steel, should be cleaned and sanitized daily. Ferrets usually prefer to defecate in one corner of the cage; like the cat, they can be trained to use a litter tray, which allows easy removal of excreta between weekly sanitation of cages [6,23].
Bathing
Ferrets do not require routine bathing, though they enjoy playing in water if given the opportunity of a shallow tub of water. However, if the musky odor becomes too strong, particularly during breeding season, a mild ferret or cat shampoo available commercially can be used. Frequent bathing, that is, more than once a month, may cause drying of the skin and pruritis. Provision of bedding such as hard wood chips or pine shavings may also aid in maintaining breeding male ferret coat condition.
Management
There are several factors to be considered in the proper management of ferrets.
Handling and Restraint
The domesticated ferret, unlike another closely related mustelid, the mink, is considered to be inquisitive and to have a gentle disposition. The animal is often handled without protective gloves, and in pet settings, is commonly allowed free access to the household; caging can be used at night, though, or for periods when the owner wants the animal to be confined. Ferrets that are hungry or ill, particularly males and females with litters, can exhibit aggressive behavior and bite unsuspecting handlers. Frequent handling, as well as neutering animals at weaning (8–10 weeks) or prior to puberty at 6 months, minimizes aggressive behavior. It should be cautioned, however, that some pet ferrets allowed free access to the household have been known to traumatize infants severely (see Chapter 1).
If injecting ferrets with medication or performing a physical examination that may alarm the animal, it is wise for the person holding the animal to wear protective gloves and to grasp the animal firmly at the nape of the neck with one hand, and to extend and support the body with the other hand (Fig. 6.13). Alternatively, the ferret can be handled safely by one person for subcutaneous injection (Fig. 6.14). The ferret can be restrained manually by placing the forearm of the ferret between the index and middle finger (Fig. 6.15) (see also Chapter 11). For oral medication, the animal can be placed in a cat-restraining bag if necessary or wrapped in a towel. Minimal restraint, however, is required if the medication is mixed with Nutrical (Evsco, Buena, NJ) and the medication is placed on an application stick. Most ferrets readily eat this mixture.
Fig. 6.13. Manual restraint of a ferret. Support of the hindquarters and restraint of the head are important components.Fig. 6.14. Restraint of a ferret's hindquarters for injection or insertion of a rectal thermometer.Fig. 6.15. Manual restraint of the forelegs of a ferret. Note paw between forefinger and middle finger.
Appropriate tranquilizers or anesthetics can be used effectively when handling fractious animals (see Chapter 12).
Identification
Subtle coat color difference, body size, or behavioral traits are often sufficient to distinguish a particular ferret from a small group of cohorts. If, however, large numbers of animals are utilized, individual markings or tags on the animals are required. In our experience, ear tags have been used successfully for a number of years. The procedure is atraumatic in young ferrets, and the pinna of the ear reacts minimally. If an occasional tag is lost, another can be inserted easily. Ear notching or tattooing the ear can be attempted, but the size of the pinna poses limitations to these procedures [2]. Microchips are easy to implant and work well for identification. They can be placed in ferrets as young as 2 weeks of age. The albino ferret can be marked with indelible dyes. Alternatively, the inner thigh can be tattooed; ferrets must of course be anesthetized during this manipulation. In pet animals, collars are sometimes used.
References
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17. Fuller CC, et al. (2008) A multi-state Salmonella typhimurium outbreak associated with frozen vacuum-packed rodents used to feed snakes. Zoonoses Public Health 55: 481–487.
18. CDC (2012) Multistate outbreak of human Salmonella infantis infections linked to dry dog food (final update).
19. Bleavins MR, Auberich RJ (1981) Feed consumption and food passage time in mink (Mustela vison) and European ferrets (Mustela putorius furo). Lab Anim Sci 31: 268–269.
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