We just caught the fox we have been trying to trap for months.... AND we did not catch him in the trap....
I have a burn pile in my back yard for yard debrie. One afternoon, I dumped some hamburger grease on the pile.
That evening we went out about 30 - 60 minutes after the sun set and found the fox eating the grease in the burn pile.....
So, I recommend bacon or hamburger grease as your bait. It will draw them to your space, but I don't know if it will be enough
of an incenative for them to crawl in the trap....