Hi!
I wrote a post on this before somewhere but can't find it.
Anyway, here goes:
Some piggies can be "trained" and some can't or just don't want to be. This is the first thing to remember.
Secondly, it is reasonably possible to train them to poop in one area but getting them to pee in one area is almost impossible.
With that in mind, he's one way to try. When you get all 6 out for floor time, cover the whole area with the material you want to use for their toilets (newspaper, toliet paper or whatever). They will happily poop and pee all over the place and that's fine. You need to do this for a while, like two or three weeks, everyday.
Once you've done this, you can start reducing the area that's covered. In this way, those piggies that are inclined will continue pooping and peeing only on that surface. Eventually you can reduce it right down to a couple of corners (over the course of say another two weeks).
The next stage is to introduce the toilet you want (if you want one) like a corner litter tray or a covered tray or whatever you think will fit nicely in your cage. First introduce this at floor time. In the corners you've got them using with their covering (the paper or whatever). Put this covering in the litter tray for a week or two and you will see if the trainable piggies still use these corner and the litter tray.
Finally, you can now try to introduce this toilet to your cage. Thos piggies that get the idea and are inclined to use it will now pretty much stick to this for their business. Those piggies that don't want to won't.
Once you have this done it's important to clean out this tray etc. everyday. A piggy that like to use a toilet area also like to keep clean and once the toilet area is full, wet or dirty, he/she will be off using another area.
We have two boars. One is pretty clean, poop and pees in one corner where we put dwon toilet paper. He will only poop/pee in another area if we slack on spot cleaning. The other boar basically goes wherever he wants to and that's fine. You've got to be prepared for that.
I hope that helps
