Yes they are very competent egg and chick thieves! They also eat rodents and possibly copperheads though so I leave most of ours alone, except for the one that got into our coop. Since he then knew where this great source of eggs was located, we stuck him in a pillowcase and drove him to a cattle pasture two miles away, where he could be a help instead of a pest.Speaking of snakes.. I had a snake in the duck coop yesterday. Luckily it was just a rat snake, so I encouraged him( with a water hose) to enter a trashbin and released him across the street from me, into a large field going the opposite direction of my house. I'm really quite shocked that the snake could climb that high to get into the coop!
Did your get in through those gaps between the metal roof and supports? I use metal roofing too, but put those filler pieces in so there aren’t gaps... I try for no more than 1/2” gaps. You have a lovely setup, by the way!