Best thing is to put a shotgun by the door and go out there every 2 hrs and shine the light and u know the rest. Besk keep the chickens locked up too and have a roof over their heads. A hungry fox will climp a fence. For your bait use any thing, I caught one with some old mashed potatoes one time. I catch coons with a uncooked hot dog right out of the package so give that a try or just some unwanted table scraps. Good luck!!!!
This time of year foxes are hungry and not too hard to trap. Your trap and set need to be fairly clean of human scent, but it is near impossible to make a set that the fox will just walk right up to. They are by nature suspicious of anything they sense humans have touched. Good luck and if you live where you dare shoot, teach your wife to use even a .22 LR rifle and next time she can shoot it if it dares come around in the daylight. I would even suspect it is sick to be hunting in daylight, but they are a creature of opportunity, eating when they get the chance.