That would be a chicken snake, just like the one i killed the other night, looks like it wants in pretty bad, lol, glad you have you coop very secure, because if there is a way in, it will find it!!!
This just happened....I was reading this thread...because I have been gone on a trip...neighbors were caring for my birds while I was gone...found my last pullet dead in the coop when I got home...head was all slick with dried fluid...I could see where a snake had constricted it...took it out...
Everything kills a chicken, those black snakes are not called "chicken" snakes as a joke....lol....i caught one on my porch last year, grabbed him and transported him down the road a mile, he was back the next week, so i killled him, once they find eggs, they will not stop. Raccoons are terrible...