I just want to say that this doesn't sound like a breed problem to me. In defense of the pits, my dachshund can and will kill any chicken she gets a hold of and she will do it fast and with an efficiancy that is terrifying (If you are a chicken). Although she has tons of obedience, she has a really major prey drive. I have been getting her ready to do earthdog in order to channel that energy positively, but aside from my presence, if she ever got out alone with chickens, she would destroy them. But just because she kills chickens doesn't make her agressive to kids, babies or people, in fact she has worked as a visiting/therapy dog in rest homes. She loves babies and cuddles them. As her owner, i keep the chickens away from her in a very secure pen. Prey agression varies dog to dog and breed to breed. I have owned a lot of powerful dog breeds, and I am honestly not surprised this happened with 2 teenaged dogs left alone with something interesting and noisy like chickens. Dogs don't automatically know whats off limits or not, and 1 year old dogs will test all kinds of boundries. Do you know that more dogs (of all breeds) are relinquished at 1 year of age? Why? People don't understand that this is a phase in which the owner needs to work the hardest in training and exersizing active teen puppies. If you are uncertain about your pits, I suggest you take some formal obedience classes. You will gain confidence as you learn how to train and correct your dog effectively. Also, if you can, replace chicken wire with hardware cloth or an overlay of chain link, or add the hotwire. Or both.With powerful breeds comes great responsibility on the part of the owner.