I had a raccoon CHEW the front door of our coop, which is an old tool shed modified for the flock. Its plywood, and that crafty coon was able to chew a hole in the door just big enough to get in. Problem was after he ate one of my roos, he was too fat to get back out. In the morning I had a surprise. When I went to get the eggs, there were a bunch of frantic birds out in the run, they werent acting right. Huddled up together, squaking and nervous. I noticed I was missing a rooster, and when I opened the door there was a roo body and a raccoon. It was in the corner, hissing and looking mean. I closed the coop door, ran into the run and closed the pop door, and got the .22. Shot the coon right in the coop. I THOUGHT my coop was pretty secure, but I guess this critter was determined. Hope he enjoyed my rooster as his last meal.
Coons also have opposable thumbs, and they are pretty smart. They are fairly good at opening simple latches. We just had a hook/eye latch on the pop door then. We have a much better latch now.
I also have a friend in NC that keeps a backyard flock. They live in a very isolated area, and have had everything from opossums to bears get into their coop. They just lost a few birds recently to coons that peeled up the metal roof on their coop. There were 1" ventilation holes around the top, and the coons were apparently able to get their hands in the hole and peel back the roofing material just enough to squeeze in. Crafty little buggers, thats for sure.
From my experience, the raccoons will try, but give up if its a more trouble to get in thAn they want to go thru. But it all depends how hungry they are and what other options for dinner they have in your area. right now theres plenty for them to eat, but they are also teaching their young to forage and hunt, so that comes into play as well. Babies are born usually in april or may, and this is the time of year they are learning to fend for themselves, so mama coon may be a bit more patient when it comes to scoring a meal