Yes, including hay in the litter box can help encourage litter training and good litter box habits in rabbits. Rabbits have a natural inclination to munch and poop at the same time, so placing a pile of fresh hay in one end of the litter box can attract them to use it. Alternatively, you can provide a hay rack near the litter box to achieve the same effect. This practice is especially beneficial for multiple rabbits to establish their individual litter box preferences.