With no visible entry point for a body grip, what is your best advice for trap, lure, bait to catch the chicken killer? Thanks!

I'd look everything over again for an entrance, or set up trail cams, but this will probably result in more chicken deaths.

the best bait would probably be a chicken.

Small cage traps is what I use for mink in an enclosed area. They are pretty easy to guide into trap if you are on the entrance corridor. Some chicken parts and feathers should do it.

conibear box with chicken carcusses in them or liver or mouse meat