Training
Commands
When your bunny is relaxed around you it will be possible to teach it a variety of commands. An important command to learn is 'Come' followed or preceded by the name of your bunny. If your bunny learns to come whenever called you will always be able to find it, whether it's under the sofa or behind the TV.
To train the bunny to follow a command use their favourite treat and offer it to them from a close distance while saying '(Bunny name) Come', then repeat the command from a slightly greater distance. Every time your rabbit comes give it the reward. Work on this daily for a few weeks and it will soon learn that there is always a treat when it answers the command. After a while you can reduce the treats and only offer the reward every so often.
Litter Training
Rabbits can be trained to use a litter tray just as a cat can. Neutering your bunny will make this much easier as it will remove the bunny's territorial urge to pee where you'd rather it didn't.
Litter trays are available in a variety of shapes and sizes. A popular one for rabbits is the corner tray which can fit snugly in the corner of your rabbit's cage or pen and be tied down in case your rabbit chooses to toss it around. Cat litter trays with a rim along the top are useful if your bunny is quite big or if it keeps backing its bottom over the edge of its tray by mistake.
Whether indoors or outdoors, rabbits can easily learn how to use a litter tray as they are quite hygienic and generally choose to pee and poop in one area of their cage or pen. Just put the litter tray in this area with a little soiled material inside it so they recognise their own scent and realise that they have to use the tray. If they have more than one area you will need more than one tray but once the rabbit has learnt to use the trays you can reduce them.
To begin training try to lock your rabbit in its cage for 48-72 hours and during this period put any stray droppings into the litter tray. Once the rabbit has started using the litter tray regularly you can then start to increase its space making sure you put a tray wherever the rabbit chooses to pee. You should also watch it closely and gently shoo your bunny into the cage when it begins to pee while saying a command such as 'no' or 'litter box' repeatedly. Offer treats to reward your bunny when it has performed in the right place and do not scold it when it has made a mistake.
Litter training isn't always done quickly and some rabbits can take weeks to learn, but it pays to be persistent. Older rabbits are easier to train so you shouldn't worry about re-homing an older house rabbit and expecting it to learn new tricks. Training is not always 100% effective and your rabbit may still choose to drop some pellets around its space, try to be conscientious and clean up after it every day to help you notice any changes in health or behaviour and to keep things clean and hygienic.
The litter should be dried wood-based pellets, absorbent and dust free. This type of litter can be disposed of in your garden recycling box or used as compost. It is not suitable to use clay based or any type of clumping litter as this could be dangerous to the rabbit if ingested. As an alternative you could also try layers of newspaper in the tray with hay on top, provided that the ink on the newspaper is soy based and your rabbit doesn't eat a lot of paper.
To encourage good litter habits you could try putting a layer of hay on top of the litter, rabbits love to chew while going to the toilet. You might find that your bunny will relax and spend a lot of time in its tray; this is natural and does not need to be discouraged.
Regularly replace your bunny's litter, at least every 2-3 days. White vinegar is a brilliant cleaning agent which removes bad smells and dried urine. However, do not make the litter tray too clean in the training period, as your bunny will get confused and forget what it is for.
After successful training, if your bunny stops using its tray and pees in other places this could be a sign of illness and you should consult your vet.