Breeder of Mini lop & Netherland Dwarf Rabbits based in Ayrshire, Scotland

Litter Training A Rabbit???

Yes rabbits can be trained to use a litter tray, Humphrey my large cross uses a litter tray in the corner of his shed. I use a plastic tray filled with a mix of wood pellets and wood shavings. 

If you plan to keep your rabbit in the house litter training is pretty essential.
Most rabbits take to using a litter tray quite easily, rabbits like to do their business in the same place so to train your rabbit to use a tray should be quite simple

Tips to helping your rabbit use a litter tray in the house (hutch or shed) :

Adult spayed or neutered rabbits are much more consistent with using a litter tray than unaltered and young rabbits. That doesn't mean you can't use a box with young or unaltered rabbits - you just might not get the best results all the time.

Before giving your rabbit the run of the house place a litter tray in the cage, get some already deposited droppings and wet shavings and place them in the tray, this along with placing the tray where the rabbit usually does its business will hopefully mean the rabbit will continue to use the same area - but do it into the tray. Once your bunny is consistent with using the tray     in his cage, then let it out into a small area/room in the house with multiple litter trays to choose. The rabbit will then choose an area/tray it prefers, later you can remove the extras. After it masters a room, the bunny can have more space. It is confusing to   a rabbit to be given too much freedom all at once, so let him learn at his own pace in a small area first.

If your bunny keeps using a cage corner opposite the litter tray try moving the box. You can use wood shavings/hay/straw or a bunny safe litter, never use clay cat litter.
Many rabbits will use droppings to mark territory. This habit is significantly reduced or eliminated with spaying and neutering, but is more likely to be a problem if there are other bunnies around. Some rabbits who are perfect with their litter tray will start leaving droppings when their environment changes or they are stressed.

Good Luck