Without more information, it's hard to tell what you should be feeding them. The easiest rule of thumb is to feed them rodents about the width of the widest part of your snake's body. For full grown snakes, this can mean a small or medium sized rat. If you are still feeding mice, switching to rats will make feeding them in the future much easier as they will only need one rat for a feeding. I typically feed a rat a week to all my BPs and err on the smaller side when it comes to the size of rodents.
As for housing, they should be housed separately and given a proper temperature gradient and hides. The easiest way to do this is actually in simple plastic tubs and there is a guide on how to do it here: http://ball-pythons.net/forums/showt...e-Basics-*DUW*
There is tons of information on this forum if you want to learn more about your snakes. The husbandry forum is the best for getting their living conditions set up right.
As far as snakes biting, their bites are generally very benign and only happen for one of two reasons: feeding or fear. You will learn to recognize when your snake is in one of those states and there are plenty of techniques to snap them out of that mode, the easiest one being to pick them up from behind so they can't bite you. Lastly, if a snake bites someone, it's no reason to kill it. That's just inhumane and cruel. If you don't want your snakes, put them up for adoption or talk to your local herp society about surrendering them.