lots of snakes can get messy! but i dont there there should be a build up of urates... the one smallish breeder i visited (Mr. Brian Gundy of for-goodness-snakes.com) had at least a hundred BP's some cages had some mess but it was some daily mess, upturned waterbowls etc.... only 2 of his BPs showed any signs of aggression/defensive behaviours, he has a sweet high contrast albino baby that did try to strike but it was maybe a couple months old so im certain it was defensive, and another young male normal let out a hiss when he went to put him back in his tub. i can see how it would be hard for breeders to work full time clean cages all night and get time to handle the animals so those animals might need a bit more one on one time to get them tame. just my 2 cents from what i have seen so far. either way you choose i hope you find what you are looking for