Rabbits over a year old are of the best age to litter-train, since they are calmer and neater than adolescents. This is especially so if they have been neutered. It is essential to have your rabbit neutered if he is going to live indoors, as it reduces spraying and generally makes it easier to house train them.
Having more than one tray will increase the chances of success. After a while, you’ll be able to remove the trays he uses less often. You should use a tray with 3 high sides to contain the litter and 1 low side to allow easy access. You should use newspaper as a base, with a thick layer of hay, straw or non-clumping cat litter. Avoid pine shavings or sawdust if you can.
Even if your rabbit is to eventually have run of the house, it is better to start him off in one room. The kitchen or bathroom is probably best, assuming they are not carpeted. Fitting a gate across the doorway is a good way of confining him without isolation. You should put one tray near his bed and one in the corner of the room. It is a good idea to put some urine-soaked bedding or pellets in the trays to acclimatize him. Try to lure the rabbit into the tray and issue lots of praise when he gets in. This way, he will associate nice things with being in the tray. If your rabbit urinates outside the tray give him a short, sharp ‘No’ and put him in the tray. You will make being in the tray seem like punishment if you chase him into the tray. Never shout at or hit your pet as this will only frighten and confuse him.
For litter-training to work, you must make the tray as inviting as possible. You can use treats and different types of bedding depending on what he enjoys doing in the tray. That is, if he enjoys taking a nap, put soft bedding in it. The more your rabbit enjoys being in the tray, the more likely it is to want to mark it with her urine.
If your rabbit has already developed a habit of doing the toilet somewhere (like behind the sofa), you can move the tray to that spot. It is important not to expect too much of your rabbit – when you are not at home confine him to a smaller room so as to avoid too many ‘accidents’.