The turkey won't be any match for a fox or coyote. Could it be an owl? Your trap won't catch that (the only reason I ask is, a friend of mine went out to her barn one night to lock up her birds and an owl flew in the door right over her head). I still think that securing your barn for the night is the best way to keep the chickens from getting eaten. You might catch whatever has nabbed the three you mentioned, but with an open door, you're inviting all kinds of other predators, too - more coyotes, fox, coons, possums, owls, stray dogs, mink.... the list goes on. Birds can't defend themselves at night.