[bewitched]

I agree that if they are feral and being trapped for euthanasia, they are far better off as barn cats. I would also say cats from a kill shelter that have been scheduled to be "put down" are lucky to be rescued and become barn cats.

If you keep them shut in the barn for a while before you allow them to roam free, they will be more likely to view your barn as "home base" and not run off.