It's a very common misunderstanding: many people give pellets as the main course and hay as the side dish. In a rabbit, the correct order is exactly the opposite, and that difference explains a good part of its health problems.
The myth of pellets as the main course
Pellets are convenient, concentrated and rabbits tend to love them, so it's easy to fall into giving them freely. The problem is that a rabbit that fills up on pellets eats less hay, and in doing so loses the long fiber its digestion and teeth need.
What should be the base
The base of the diet is hay, available at all times and making up around four-fifths of what the animal eats. It's rounded out by a daily ration of suitable leafy greens and a small, measured amount of quality pellets. In that scheme, pellets are an extra, not the center.
Why too many pellets do harm
Too many pellets provide a lot of energy and little fiber, and that translates into excess weight, teeth that don't wear down properly, and digestion that works worse. Many of the dental and digestive problems seen in rabbits stem from a diet with too many pellets and too little hay.
How many pellets is reasonable
For a healthy adult rabbit, a small, measured amount a day is enough, and some rabbits that eat plenty of hay and good greens barely need it at all. The exact amount depends on the animal, so it's best to adjust it with your vet rather than leaving the pellet feeder always full.
