I just asked this the other day, but did not get a response yet. I am worried about this also. My pig is showing signs of a UTI again and I am wondering if this is how she got it again.. They keep peeing and pooping in their hay, so I took their litter box out, made a coroplast one lined with underpad, towel and fleece, then took a kleenex box and filled it with hay so they could not jump into it, next to my coroplast litter box lined with fleece I made them.. I am gonna make a hay rack out of coroplast, there is an awesome design in the photo gallery, compliments of Lissie that I am gonna make, SOON! I do not know the answer to this, but I changed the way they are getting their hay today, till I build this other one in the next week. This way, they stand on the fleece litter box to eat their hay out of the kleenex box I stuffed full next to their tray and the pee wicks through instead of mixing in their hay.. I am just worried this is how my pigs may have got an UTI from one another again, maybe? Nevertheless, I figure if i am right or wrong, if they have a bladder infection again, I can make sure their hay doesn't get any infection on it.. I am curious to hear a response in this