While most pet rabbit diets are geared towards ensuring that rabbits do not become overweight, there are some rabbits that you wish to fatten up quickly. Rabbits which are recovering from a long illness or rabbits that have been rescued from neglectful situations may be too skinny, and require fattening up before they may be considered healthy. Fattening up a rabbit healthily is a priority for rabbits that are underweight.
Take your rabbit to the veterinarian. It is important to ensure that your rabbit is free of parasites or other medical issues that might be causing continued weight loss. Also speak with your veterinarian about medication that can enhance your rabbit's appetite and foods the veterinarian can suggest for weight gain.
Install a water bottle or water bowl in the rabbit's cage. While all rabbits need to have fresh, clean water available at all times, skinny rabbits may be especially dehydrated. Watch the water levels closely and keep the water source full at all times.
Keep a food bowl full of Timothy hay pellets in your rabbit's enclosure. While Timothy hay pellets are typically not recommended as a permanent food item, they are helpful in putting weight back on a recovering rabbit. They are specifically used by people who breed meat rabbits to put weight on their animals.
Give your rabbits a treat of fresh fruit every day. Feed a rabbit 1 tablespoon of fresh fruit for every 0.907 Kilogram of body weight. Some acceptable fruits include pears, kiwis, strawberries, apples, pineapples and melons.
Weigh your rabbit on a scale every week. This helps you chart your progress and it also lets you know when your rabbit has reached an acceptable weight.
Avoid feeding your rabbit grains, refined sugar or beans, even if you are trying to fatten them up. While a rabbit will plump up on a diet including these foods, they can also develop a gastrointestinal disease.