Underweight Rabbits and Foods for Fattening Rabbits

Underweight rabbits
Written by Editorial

Noticing your rabbit pet thin and emaciated can cause a lot of worry. What makes it underweight and what can be done?

Most people often struggle with obese and overweight rabbits. However, it is possible for this pet to be skinny. Although not common, it does happen.

Underweight rabbits
Underweight rabbits

A rabbit will be considered underweight if it is more than 10-20% below the ideal body weight. This depends on its breed, and you can get use a rabbit weight chart from ARBA know ideal weights for different breeds.

Signs you may notice

It is an obvious thing to see if your rabbit is underweight as it will look thin, fragile and weak. Some signs it may include.

  • Emaciated appearance characterized by sharp, prominent to easily felt hip, pelvis, rib and spine bones due to a very thin to no fat layer and muscle loss.
  • Its rump may also be curved inwards, and the “abdomen “caved in” rather than smooth at the area bordered by the last rib, the thigh, and the spine (sort of a triangle).”[1]
  • A rough and dull coat
  • Lethargy
  • Fever, drier and small dropping

Others may include typical behavior like its search for something like food or water, food that it has not eaten may be dropping, and pain or injury that may make it have a hunched appearance, unable to move, or closing its eyes.

Causes of underweight in bunnies

Reduced food intake and decreased appetite, often occasioned by a medical condition or such as a dental, cardiovascular, liver, pancreas or kidney disease, arthritis, cancer among others. They cause pain, cause toxin buildup in the brain or other organs making it difficult for the rabbit to eat and it may lose appetite. In the case of respiratory disease, your rabbit may be unable to smell food.

Wrong diets especially excessive fresh green veggies as they are full of water and might not provide the required calories besides causing stomach upsets. Rabbits require unlimited hay supply, some pelleted foods, green veggies and treats including fruits. Do not forget water is essential too.  

Feeling afraid especially due to loud noise, predator smell or noise while it is in its feeding area. This may make it anxious and thus not eat.

Also, if you keep them in a colony, the dominant one may make it difficult for others to eat and this may cause them to lose weight.

As a pet owner, always be on the look for any signs such as it not eating all over a sudden, spending over a day without eating anything or reduced droppings as they could be signaling a life-threatening condition.


Diagnosis will involve a thorough physical exam to see if there are any dental problems such as overgrown teeth (especially molar spurs), looking at its environment as well as laboratory checks.

Laboratory checks may include urinalysis, serum analysis, blood count, and radiographs to help pinpoint on some of the diseases we have mentioned that might make your pet not to eat or lose appetite.

For instance, in case of a dental problem such as elongated teeth, dental abscesses, and misaligned, all that incisors that may harm their inner soft tissues, lateral-lateral skull X-ray and physical observation may help unveil such a problem

Recovery and fattening foods

Once the diagnosis is done, in case any ailment or injury is causing the weight loss, your veterinarian will treat it where possible. Some conditions such as arthritis may be a long-term problem, and your vet will advise you on the care required.

Also, try to give your pet a serene environment especially if you have other pets such as dogs and cats or even your children as they may not know how to handle it properly, causing anxiety. Also, if it eats slowly, give it enough time to feed.

Thirdly, to help it gain muscle quickly, you also need to help stimulate physical activities such as giving it the various rabbit toys, a rabbit run or pet to play in and so on.

Besides treatment, and giving it a serene environment, you need to come up with a proper diet to help it fatten it. Here are some essential tips to bear in mind:

  • Do not switch to pellets only thinking they will help it fatten quickly. Rabbits are likely to benefit from fiber-rich foods such as grassy hay (especially the second cut) and some limited amounts of leafy greens. High fiber diets have many benefits including healthy teeth and gut.
  • “Alfalfa can be given to underweight rabbits, only if calcium levels are normal.”[2] It is higher in protein. Unfortunately, it is also higher in calcium. Give it small portions.
  • Dried foods especially pellets for pregnant or lactating does as well as those growing ones may help since they have a high protein and calories. However, ensure they also have high fibers.
  • Give them treats of non-leafy vegetables and fruits such as apples as they have lots of calories and may boost appetite. Oats are also good for weight gain.
  • If your bunny is elderly, it may need a different diet slightly, e., higher in proteins for instance
  • Severe cases may require you to syringe-feed them since they often do not keep much reserve energy in case of anorexia. Do this until they are stable and able to eat again.

While trying to change their diet, always look at how their stomach responds to the new foods and do it gradually.

Commercial foods for weight gain

  • Oxbow Critical Care – It is high in fiber with no added sugar, comes in banana and apple flavors, and it will support your bunny’s nutrition needs.
  • SARx PLUS for rabbits – Designed for weight gain, has most nutrients that rabbits need and will boost appetite
  • Carefresh Alfalfa Hay Food – Good for dental health, has a high protein content, it is pure alfalfa and can help your rabbit gain weight


Begin by identifying the cause of weight loss in your rabbit, give it a good peaceful environment and introduced healthy foods that will help it gain weight gradually.

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