Your pits must have a really high prey drive. I have 2 pits and a pit mix.. plus 2 basenji mixes, a shar-pei/boxer, and a husky mix. The apha dogs are the basenji mixes (and they're the oldest and most decrepit- go figure). The one at the bottom of the pack hierarchy is the pocket pit (she only weighs 35 lbs). We also have 3 cats.

Granted, the pocket pit has a very high prey drive and will kill any strange cat that wanders into our back yard.. but ours are safe in the house with her.

I do love my pibbles, tho. =)