If you notice your pet rabbit is shedding its fur more than usual or loosing patches of fur, it is most likely just normal moulting. A rabbit will moult at least some of their coat regularly. Adult rabbits can be expected to moult completely once or twice a year, although with some rabbits it can happen more frequently. A young bunny will lose its baby coat between 3 and 12 months old. Moulting time frames, effects and patterns of hair loss will differ from rabbit to rabbit. However, excessive moulting can be a sign of nutritional or environmental problems. There are also signs to watch for to determine if hair loss is caused by fungus, parasites or a medical condition.
Moulting vs. Excess Molting
Moult will sometimes first develop in a pattern on its forehead that will resemble a widow's peak, later spreading to the back and rest of the body. Some rabbits shed all over and no area of the coat will look particularly bare, while others might develop bare stripes down the back. Moulting can occur quickly, with the rabbit losing dead fur and replacing it with a new coat in a matter of a couple of weeks. Others will moult over a longer period of time. In older bunnies, moults may occur more frequently and last longer.
Excessive moulting -- when your rabbit appears to never stop losing its fur -- can be a sign of a dietary deficiency or temperature issue. Increases in protein levels in food can trigger moulting, as can increases in temperature. Alfalfa hay is high in protein and if your rabbit is eating too much of it, in addition to pellet food, it can cause the moulting problem. For dwarf breeds, protein in food should not exceed 15 to 16 per cent, while the level should be about 18 per cent for wool breeds. Sudden increases in temperature can also be the culprit. Keep your rabbit's feed and temperature consistent to prevent excess moulting, which is stressful to the rabbit's system.
Fur loss under the chin may be caused by an abscess, which is more common in male rabbits. Scent glands under the chin can become clogged and get infected. Check for legions or lumps to determine if an abscess has formed. Abscesses will require prescription oral antibiotics and your veterinarian may need to lance the boil if it's too large to be treated solely with medication.
Missing fur under the chin and in the upper chest may be a sign of a condition called wet dewlap. Most common in females with large dewlaps -- the fatty deposits under the skin in the chin and chest area -- this condition is most often caused when the dewlap area gets repeatedly wet when the rabbit drinks from a water crock. To treat wet dewlap, clip the fur to provide good ventilation to the skin and switch the rabbit to a water bottle. Fix the bottle high in the cage so the rabbit will need to stretch to reach it. If you smell a foul odour or if the irritation is severe, the wound may be infected. Consult your veterinarian for treatment.
Fungi and Parasites
If you notice small, ring-shaped bald spots on the rabbit, it may have ringworm. Ringworm is a skin infection caused by a fungus. The skin will be pink or red around sharply defined edges with a lighter tone in the centre and may be raised or scaly.
Ringworm is highly contagious to other rabbits and pets, as well as humans, so use care treating a rabbit with ringworm. The cage will need to be cleaned and sanitised with a bleach or iodine solution to contain the disease. Clotrimazole cream can be used topically on the rabbit. Wash your hands immediately after handling the rabbit and keep it isolated from other pets. If you see white dander along with fur loss, the cause is most likely fur mites. Consult your veterinarian for treatment.
Footpad Fur Loss
A rabbit's footpads should be checked regularly for hair loss. If hair on the feet is wearing thin, provide your rabbit with a resting board. Cages are available with plastic resting boards built in, or you can just place a board in the cage where your rabbit can sit to get off the wire floor. Snap-on flooring covers are also available that are vented to allow urine to pass while covering the wire with smooth plastic to prevent foot damage.