Transition Feeding

Rabbits have sensitive digestion, especially juveniles, so it is very important to slowly transition them onto any new foods whether that be a different brand of pellet or a new green/vegetable being fed as a treat.  When the rabbit is very young, it slowly nibbles the feed that the mother is eating (as well as her cecotropes) which gradually primes its digestion for that type of food.  Feeding something very different suddenly, such as fresh greens if they were only used to pellets and dry hay, can be fatal.  Because of this, it is very important to feed them the same food that they were started on and slowly transition onto anything new.  When going from dry to fresh foods, the risk is much higher so we recommend waiting until the rabbit is an adult (6 months of age) before slowly introducing the fresh treat.  

We send all rabbits home with a small bag of the pellets that they have been eating.  If you can find the same pellet, it is ideal to continue with that.  However, a similar, quality pellet can be introduced by gradually changing the proportions from mostly original food to mostly new food over about a week.  Offering plenty of dry grass hay can help this process and is a very low-risk food.  Watch for signs of a new food not agreeing with the rabbit such as loose stool or loss of appetite.  

Why do we recommend a quality pellet as the rabbit's main diet?

First, what is known about what nutrients a rabbit's diet should contain?

The National Research Council (NRC) publishes the standards for the nutritional requirements of animals including rabbits.  All animals have certain "requirements" for macronutrients (i.e. protein, fiber, fat, and carbohydrates) and micronutrients (i.e. vitamins and minerals) that are needed for their bodies to perform basic functions like providing energy, maintaining body structure such as muscle and bone, and regulating the chemical processes in the body.  Dietary recommendations for rabbits should be using these nutritional requirements as the baseline for their recommendations, but unfortunately, many do not.  If you are already feeding your rabbit(s) a certain way, I encourage you to look at the nutritional label of what you are feeding and compare it to these requirements.  

There is no one-size-fits-all diet for rabbits with nutritional requirements varying by stage of life and production (see table below).  There are certainly other factors impacting nutritional requirements with one example being Angora breeds commonly fed a higher protein feed to support fiber growth (Lebas et al. 2010), so other considerations such as that will impact how to balance the rabbit's diet beyond general recommendations.

Below is a simple table including some of the main nutritional considerations (see sources for a more expansive list) for the four main stages of life and production.  Included are the recommendations by the National Research Council (NRC) for rabbits in addition to work done by F. Lebas who reported slightly higher nutritional requirements in many situations.  

You can see that "maintenance" rabbits have the lowest nutritional requirements.  Maintenance rabbits are rabbits that are fully grown and are not pregnant or raising litters, so pet rabbits, adult bucks, and does that are not actively breeding would fall under this category.  Growing kits and pregnant does have similar requirements of more digestible energy and higher protein especially.  Does that are nursing kits have notably higher requirements as well and it is very important to make sure they are meeting these requirements for adequate milk production and to allow the doe to maintain her body condition.  

What happens if a rabbit's diet does not align with its nutritional requirements?

While this is by no means an exhaustive list, some symptoms of nutrient deficiency or excess are listed below.  Deficiency is usually caused by feeding too much hay, a low-quality pellet, or an incomplete component diet.  Nutrient excess is usually caused by feeding too many treats, feeding the wrong pellet for the rabbit's life stage (such as unlimited family pellets formulated for lactation to a maintenance rabbit), or an incomplete component diet.

Should you feed a rabbit mostly hay?

Often, you will see recommendations that rabbits should be fed a diet of mostly hay, suggesting 80-90% of the diet.  Let's look at how hay compares to the nutritional requirements of rabbits above.  Timothy hay, which is very commonly recommended for rabbits, averages only 8% protein which is below requirements for all stages of life and production including a maintenance rabbit.  It also averages 1800kcal/kg of digestible energy which is also below requirements for maintenance.  Alfalfa hay, on the other hand, tends to be 12.9-18% protein depending on maturity which can perfectly meet protein requirements depending on the quality of the hay, although the calcium content of alfalfa can be too high at 1.2% on average, causing it to be avoided or limited by many.

The quality of hay makes a big difference in how nutritious it is.  If you feed packaged hay from the store or buy tested hay, you can check the feed label for nutritional content.  If you feed untested hay, you can try to estimate what it may contain based on the grass/legume content and the quality of the hay and compare it to averages for hay of that type and quality.  When the plant matures past its peak quality, the cell walls become more lignified and increasingly less digestible, especially including a pretty significant drop in protein content after plants move from a vegetative state to seed head production.  You want to look for young, tender leaves, stems that aren't super thick, and less maturity of seed heads in the hay.  You will also want to look for a lot of leaves compared to stems as those are the most nutritious component.  First cutting hay is generally lower quality because the plants grow rapidly in the spring and the weather conditions are often too cool/moist to harvest on time in late spring or early summer, delaying harvest to when the crop is over-mature and losing nutritive value.  That isn't to say that you can't have a high-quality first cutting or a low-quality second cutting though, so talk to the farmer, pay attention to how mature the hay looks, and try to get tested hay if possible.  Also, if you have had a particularly wet year, chances are the hay will be lower quality, as farmers have to wait for dry windows of time to harvest with plants growing very quickly in the meantime. 

Hay does not contain all the nutrients rabbits require in a day but a balanced pellet does.  Hay has value in providing additional long-stem fiber and behavioral enrichment, so we recommend feeding a small amount in addition to the full serving of pellets.  The pellets provide the nutrition needed and the hay supplements with additional long-stem fiber.    

Is it possible to feed rabbits a balanced diet that is not pellet-based?

Yes, it is certainly possible to do so but most people do not have the background in nutrition to balance a diet.  We recommend a diet (quality pellets) that is already balanced by experts in nutrition because it is very difficult to balance it on your own.  Even if macronutrients are pretty well-balanced and a mineral supplement is provided, vitamins are very hard to balance on your own.  For example, vitamin A is especially critical in a rabbit's diet.  As shown above, too little or too much vitamin A can be very dangerous.  

Feeding less than the recommended daily serving of pellets can have the same harmful effects because a full serving is formulated to contain the daily required nutrients, therefore a partial serving only contains a portion of the daily required nutrients. 

Conclusion

While there are many different types of food that can be fed to rabbits, the most important consideration is that the total ration meets the nutritional demands of the rabbit.  Timothy hay, which is most commonly recommended for rabbits, does not contain enough nutrients on its own to meet the nutritional demands.  Common recommendations of large quantities of hay in the diet without proper instruction on balancing the remaining nutrients can be very harmful to the health of these animals.  Instead, we recommend feeding a full serving of a good quality "complete" pellet that has been balanced to meet the daily nutritional requirements of these animals.