yes I have, we lost 9 2 year old hens Rhode Island Reds, Leghorns, barred rock before we were able to figure out what it was, their attacks were all different and they were trap savvy why it took so long. You get an over population they will hunt in packs, that's just the ones we trapped and relocated where there were no birds in 10 mile range, they changed strategies due to the rooster killed 2 of them. They over populate quickly and if they deplete the mice they will go after anything they can to feed themselves even if it means working together, the different attack styles may be just them learning how to safely get their prey as a team.really? Have you witnessed this? Cats are not generally considered pack animals. I have seen feral cats occasionally, they are smaller than my hens who attacked them and chased them away.