Why is my 6-month-old rabbit so tiny and underweight despite eating?

With the discharge from her nose I would suspect that she has some sort of respiratory issue going on. Rabbits are very prone to pasteurella infection and this can cause weight loss over time and make them generally unwell. With any disease rabbits will be under stress which puts them at risk of gut stasis. Running bloods could help to establish if their is an active infection and if any other organs are involved.

You are doing all the right thing it seems, this means he must be suffering from a medical condition. i would recommend to take him to the vet in order to get him dewormed. he might also be suffering from a gastrointestinal infection that is causing this. upper respiratory infections are also know n=to cause weight loss. the vet will check him and treat him accordingly.

Depending on the breed of rabbit, this may be a normal weight. As long as she is eating, drinking, defecating and behaving normally otherwise, there is likely no cause for concern. To be absolutely sure would require a physical exam with your veterinarian.

Yes, I agree, this bun looks very thin and unthrifty. It is possible that he may have parasites or some other issue going on. Is there any way you can get a rabbit-appropriate dewormer in India? I like to use feline Revolution which is a topical treatment for cats and very safe and effective used on rabbits--can you order this online?

It sounds like they could have a parasite or an infection causing the problem. It is very concerning that they both lost weight rapidly and one died. It would be best to have her examined by a vet to determine the cause and treat. Your vet can run some lab-work, if needed, and prescribe medications to treat. She may need some fluids for dehydration, antibiotics, de-wormer, etc. Besides trying to get her to eat and drink, there isn't much more you can do without veterinary care. Hope she gets better soon!

A rabbit that is not eating normally should be considered a veterinary emergency. If the GI tract slows or stops, a dangerous buildup of bacteria and toxins could endanger Bun Bun's life. Given his age and weight loss, he needs to be seen by a veterinarian...any veterinarian. If necessary, a specialist can be contacted by phone or online by your vet. Veterinary reference labs may provide consultation services as well. For now, offer as much timothy hay as he will eat. Offer some Oxbow Critical Care for Herbivores as well. You may be able to find it in pet stores or in the local vet clinic. Keep Bun Bun warm and as stress free as possible. The link below leads to a list of veterinarians experienced in treating rabbits locate din Wisconsin. http://wisconsinhrs.org/local-vets/

Discontinue feeding milk and egg yolks to Yuki. These are not appropriate foods for a rabbit. Stop the colic-aid as well. This may interfere with her gut. Rabbits require a high fiber diet to maintain gut health. Feed as much timothy hay or similar grasses as she wants to eat. She can eat alfalfa until she is about 7 months old. Offer a commercial pelleted diet as well. You can moisten it to make it easier for her to eat. Have her examined by your veterinarian or a vet experienced in treating rabbits to diagnose illness or injury. If she is dehydrated, she may need supportive care to get her eating and acting normally.