Wooden hutches are the standard and are satisfactory in many cases. Their disadvantage is that they will tend to rot with the absorption of urine and rain unless properly protected. Care should be taken with wood preservatives to ensure an animal-friendly preservative is chosen (do not use creosote!). The roof may be further protected with the felt material used to roof garden sheds and should slope to the rear of the hutch to avoid rain dripping into the front, or pooling on the roof. The hutches should also be raised off the floor on legs to avoid the bottom rotting from the damp ground surface. A ramp should therefore be supplied if the rabbits are to be allowed in and out of the hutch of their own accord. Wooden hutches are also much more easily destroyed by gnawing.
In commercial fur- and meat-producing situations, rabbits are kept in wire mesh hutches suspended above a solid floor. The wire mesh ‘hutch’ has one major advantage in that it prevents soiling of the fur by urine and faeces. However, it can cause abrasions of the hocks in older overweight rabbits and is not advised for housing pet rabbits.
Substrates used for cage floor covering include straw, hay, shavings and newspaper. Many rabbits will preferentially select hay and straw for bedding over shavings and paper. One of the advantages of the former is that they allow urine to drop through the fibre framework and away from the rabbit, so reducing the likelihood of urine scalding in older and arthritic rabbits.
Care should be taken to avoid overheating of the hutch, as rabbits cannot sweat and temperatures above 26–28°C will rapidly cause hyperthermia and death. Hutches should therefore be positioned out of direct sunlight, particularly in the summer months. Rabbits will shiver when cold, although they can tolerate cold better than heat. Care should still be taken to ensure that the hutch is not overly draughty or exposed during the winter months. Bringing it into a shed or garage is often advisable in the worst weather.
Food and water bowls
Feeding bowls should be a ceramic or metal. The former are preferable, as they are heavier and harder to knock over. Plastic feed bowls should be avoided as they are easily chewed. Water feeders are better offered with ball valve drip dispensers. They allow less contamination of the water with food, urine and faeces than an open bowl. Care should be taken with these feeders, though, as some rabbits reared with water bowls will not drink from them. In addition, the ball valve often leaks and this will lead to excessively damp substrate and mould growth. Drip feeders will also suffer from bacterial build-up and need careful cleaning once or twice a week, or even daily if a large number of rabbits are housed.
It is advisable to provide outside runs attached to the hutch in the summer months. This allows the rabbit access to unfiltered sunshine, which is important for vitamin D3 synthesis as well as for stimulating normal annual rhythms of behaviour. Fresh grass is also the food item rabbits are supremely adapted to eat. The fibre content, in particular, is vital for wear of the teeth and stimulation of normal gut motility. Grass should not be cut first and then offered however, as this rapidly ferments and can produce colic.
Care should be taken when securing outside runs to make them both rabbit proof and predator proof. For this reason, it may be necessary to bury the wire sides to any run a foot or so beneath the ground surface as does in particular will burrow regularly (see Figure 2.2). To prevent foxes and cats gaining access to the run, a meshed roof should be provided. Finally, all outdoor rabbits should be vaccinated against myxomatosis, the viral condition spread by fleas and mosquitoes from wild rabbits, and preferably against viral haemorrhagic disease as well.
Many rabbits are now kept as house rabbits, with sleeping quarters and a litter tray. Rabbits can be toilet-trained relatively easily. The first steps in this are to keep the rabbit in a small area with a sleeping area, the litter tray and a feeding area. Once the litter tray has been associated with urination in particular, the rabbit may then be allowed more freedom to roam.
Hazards in the home include electrical cabling, which should be hidden beneath carpets or protected inside heavy-duty cable trunking, which is available from hardware stores. Houseplants are another problem. Many of the exotic tropical houseplants are poisonous. Examples include African violet, Dieffenbachia, cheese plant and spider plant.
Rabbits are in general a social species, preferring to live in a group rather than singly. Problems arise though with keeping a number of entire males together, as bullying and sexual harassment will occur. Neutering is therefore advised where more than one male is to be kept and may be performed in bucks from 4 to 5 months of age. Mixed sex groups will work well if the does are spayed. This may be safely done from 5 to 6 months of age and is advisable even in solitary does due to the high risk of developing a malignant uterine cancer, known as a uterine adenocarcinoma, in middle age.
Some owners advocate the grouping of guinea pigs with rabbits. This is to be discouraged for two important reasons. One is that the rabbit has very powerful hind legs, and the guinea pig, a long and fragile spine. Consequently, one well-placed kick from the rabbit can do a great deal of damage. The other reason is that rabbits are frequently asymptomatic carriers of the bacteria Bordetella bronchiseptica in their airways. These bacteria can cause a severe pneumonia in guinea pigs. Other domestic pets are not advised to be mixed with rabbits, as both cats and dogs are potential predators!
Rabbits are a prey species and therefore communicate in a very different manner from the more commonly understood cats and dogs. Indeed, it may seem that rabbits are very poor at communicating their feelings to their owners, when in fact they may be communicating, but in a much more subtle manner.
Affection is shown by mutual grooming of a companion, or owner, with licking of the hands in the latter case common. Other signs of relaxation include coming to the owner to be fed treats, following an owner around the house and, in many rabbits, making a buzzing noise from the larynx. This may be mistaken for a disease problem by inexperienced owners as it can be quite loud!
Aggression is shown by scratching, boxing with the front legs and biting. Aggression may be initiated because of a hormonal state, such as those caused by coming into season or bucks fighting for territory in the early spring, or it may be fear or pain driven. Aggression may also become a learnt behaviour if an act of aggression results in a desired effect, such as immediate backing off by the victim or replacing of a rabbit that has just been picked up by an owner.
Fear is shown initially by the regular thumping of the hind legs. This is a warning signal. As the object of fear approaches, the rabbit will either then freeze and remain motionless or suddenly bolt towards an exit.
Chewing of almost everything in the rabbit’s environment is a perfectly normal behaviour and no amount of training will alter this fact. Owners of house rabbits should be warned of this and take appropriate action to prevent chewing of electric cables and other hazardous items of household furnishing.
Rabbit kittens are difficult to hand-rear. Many females will not foster a strange doe’s kittens, but does kept together and lactating at the same time will often allow others’ young to suckle. This is the best scenario if another known lactating doe is available. If not, as is often the case, hand-rearing may be attempted.
A rearing formula has been derived (Okerman, 1998): 25 mL of whole cow’s milk to 75 mL of condensed milk and 6 g of lyophilised skimmed milk powder. To this a vitamin supplement may be added. The kitten is fed only twice a day, from 2 to 10 mL depending on its age. This should continue until the kitten is 2 weeks old when more and more good quality hay and pellets should be introduced, aiming to wean the kitten at 3 weeks. The anogenital area should be stimulated with a piece of damp cotton wool after every feed to stimulate urination and defecation for the first 2 weeks.
RAT AND MOUSE
The common albino laboratory rat is widely domesticated. Other common varieties include the hooded rat and Rex groups. These are all variations on the Rattus norvegicus species, and the fancy rat numbers are ever increasing.
As with rats, there are many different varieties of domesticated mouse. These vary from albinos through to the Rex, whole body colour types, etc.
Construction and temperature
These are similar for both rats and mice. The traditional solid, plastic-bottomed and wire mesh upper cages are advisable. These allow good air circulation at the level of the rat or mouse. The fish-tank style of housing is much less ventilated and allows the build-up of ammonia from urine-soaked bedding. Ammonia is a heavy gas and sits just above substrate level, that is at the rat’s or mouse’s nose level, and is thus inhaled often in high concentrations in this style of housing. Ammonia is highly irritant to the sensitive mucous membranes of the airways and will inflame and damage them, allowing secondary bacterial infection. This leads to the all-too-common problem of pneumonia seen in these species.
Environmental temperatures should range from 18°C to 26°C. Because they lack skin sweat glands, temperatures above 28–29°C will rapidly induce hyperthermia and death in rats and mice. Rats can tolerate cooler temperatures better than mice, because of their lower surface area to body mass ratio and deposits of brown fat beneath the skin. However, temperatures consistently below 10°C will lead to poor health and hypothermia.
Wood shavings are well tolerated by rats and mice, but be aware that many pine and coniferous woods contain resins which may cause skin and airway irritation. Alternatively, newspaper or paper towelling may be used. Straw and hay may be used, but again beware that parasites may be introduced from wild rodents inadvertently with these bedding materials.
As with hamsters, wheels are enjoyed by mice in particular. But these should be solid in construction rather than open wired to avoid damage to limbs. Rats are less keen to use wheels, although they do enjoy climbing and hiding inside cardboard tubes and other enclosed items.
Food and water bowls
As with rabbits, sip feeders are ideal, as they lead to minimal wastage and contamination. Ceramic or stainless steel bowls are preferable to plastic.
Male rats may be kept with other males, particularly if reared together from an early age, without fighting. Females may also be paired with other females and seem to benefit from the company. Intersex groups also work well, although care should be taken to neuter the males (which may be performed from 3 to 4 months of age) if unwanted pregnancies are to be avoided. This may be done from 3 to 4 months of age. If breeding is intended, male rats may be ‘paired’ with 1–6 females. The pregnant female should be removed to a separate cage from the male rat 4–5 days prior to parturition to avoid disturbing the female at this sensitive time.
Females may be kept in groups, particularly if reared together from a young age. Males should always be housed singly, as severe fights and even death may result from aggression between sexually mature males. If breeding is intended, male mice may be ‘paired’ with 1–6 females. It is then advised to remove the pregnant female from the male some 4–5 days prior to parturition.
Rats are generally docile and rarely do they bite. Female rats are prone to cannibalism of the young if disturbed in the first few days following parturition. Food and water should therefore be provided prior to whelping, to last for the following 7–10 days, and the female then left. The female rat builds a relatively poor nest in comparison to other members of the rodent family.
Mice are generally relatively docile, although male mice may be more aggressive than females. The latter though will be aggressive in the defence of her young. In addition, although cannibalism towards her young is rare, a female mouse should be left undisturbed for a minimum of 2–3 days post-partum. It is advisable to remove the female to a separate tank once she has mated to allow her to give birth and rear her young undisturbed.
It is extremely difficult to rear young rats and mice successfully. Attempts may be made using a 1:1 dilution of evaporated milk to previously boiled water fed every 2 hours for the first 1–2 weeks. Weaning may be performed at 3 weeks. Stimulation of the anogenital area should be performed to encourage urination and defecation.
GERBIL AND HAMSTER
There seems to be one main breed common in captivity, although a separate species known as the fat-tailed gerbil (Pachyuromys duprasi) has become more popular recently. There are however several different fur colour types, with albinos, black variants and greys as well as the normal tan colouration now available.
There are four main species: Syrian, European, Chinese and Russian. Within these species there are many colour variations, from albino to red to black, with differing fur types such as the fluffy ‘teddy bear’ version of the Syrian hamster in addition to the more common short-coated varieties.
Cages and substrates
These enjoy tunnelling through deep litter substrates. It is important that the environment is kept dry, as humid conditions lead to poor fur quality and increased skin and respiratory infections. Shavings are an ideal substrate and should be at least 10–15 cm deep (see Figure 2.3). Placing ceramic or cardboard tubes through the substrate can help tunnel formation and provide environmental enrichment. Peat and other soil substrates should however be avoided due because they are more likely to encourage damp. Environmental temperatures are usually kept around 20–25°C if possible.