OK, I have been following this post, and this creature does not want to be trapped. However, it is very happy since it appears you are feeding it every night with the ineffective traps.
So, I suggest you take the very thin brass spring out of an old alarm clock. Wind it tightly around a match stick, then insert it into a piece of very tough gristle. Then carefully withdraw the match stick. Mix the gristle into some ripe hamburger and leave it out overnight in the area of your hen yard. Make sure your dogs and cats are in the house for this operation.
Most carnivores do not chew their food real well. The gristle and the spring will probably be swollowed whole. Then the digestive juices in the animals stomach will eat away the gristle and the spring will open up. I doubt the animal will survive this.
Definately not a nice thing to do, but very effective.
Rufus