Not starting this whole subject again... but where did the OP say these were positively ID'd as feral? I have managed several HIGH END properties that had groups of sub-division/neighborhood dogs that packed up and roamed and killed various types of animals from game animals to livestock. Domestic dogs have a whole different demeanor and pack type mentality than wild canines. They have a completely different social structure. Both feral and neighborhood dogs cause problems.

Collared pets are different, I agree but the owner has sole responsibility to keep their pet on their own property. The same one comes by enough, I take it home and ensure the owner understands that is last time I bring it home.

Plenty of shelters around...