Firstly, any rabbit with sores, or any form of soiling underneath its tail should be seen by a vet immediately, especially during the summer months, for one simple reason, the possibility of flesh-eating maggots.
Flies are attracted to the strong and putrid ammonia smell produced from rabbit’s faeces/urine and will lay eggs in that area immediately. Within hours your rabbit will suffer a maggot problem that will prove fatal unless treated by your vet immediately. I really can’t stress that enough.
Treatment will depend entirely on at what stage the disease is caught and can range from simply clipping and washing the rabbit’s fur to a full general anaesthetic to clean-up all affected tissues in the sad severe cases that rarely make it.
Other reasons for sore hocks can be dirty bedding, simple diarrhoea or just a basic skin infection/abcess. Either way, the best method of treatment is to gently clip all the fur off the affected areas with clippers (not scissors!), bathe with salty water, and then apply an antibiotic/anti-inflammatory topical ointment such as Fuciderm Gel (always wear gloves).
Sometimes oral anti-biotics can help too. The cause of any matted fur should always be investigated.
Get your rabbit’s teeth checked too as poor dentition can also be a cause of the runs. Probiotics can also be added to your rabbits food to help re-seed the ‘good bacteria’ in the damaged gut.
As a general precaution, always check your rabbit’s backside (especially under the tail) at least twice a day during the warmer months. Hanging sticky fly-traps around the hutch and putting a net curtain across the frontage will also help to reduce the possibility of the deadly fly-strike. Indoor rabbits can be affected too.
NOTE: This post was written as an answer to a question on the All About You website.