What part of SE MI are you from? I work all over the tri county area and could tell you about what vermin I see in different areas. I'm in Clarkston and we have raccoons like crazy. I trap with what ever food scrap we have handy, they take the bait almost every other night. The trap gets moved about once a week, they catch on quickly. We have two local packs of coyotes, but they haven't bothered us, yet. My feeling is that you had raccoons, to move that many chickens requires a big hungry animal, or several (where there is one coon...) working together. And they will dig and can sqeeze through tiny holes...