Hay is essential to a rabbit's good health, providing roughage which reduces the danger of hairballs and other blockages and should be available 24 hours a day. Hay is very high in fiber, and your rabbit needs fresh hay every day. A rabbit younger than 6 months should have alfalfa hay, but and older rabbit should have timothy hay or grass hay because it has fewer calories and calcium content than alfalfa hay. You can put hay in the ball. I can eat it and play the ball altogether.