A couple of years ago, a friend of mine was having problems with a good sized black bear raiding his chicken coop...He ended up sealing off the windows, adding strength to the door...basically turning the coop into a fortress.
He heard a commotion a few nights later...the bear had torn down the exterior wall and was exiting the coop with two chickens in its mouth.
My friend had grabbed his 45-70 on the way out and he and the bruin had a "come to Jesus" meeting (literally) there is his back yard. He threw a 4x8 sheet of 1" plywood over the breach, went to bed and buried the beast the next morning with a backhoe. He had tried to get the NHFG to help him do something about the bear but they were never available, probably rescuing some dimwit off a mountain...They always said to make his coop stronger.
Good luck with that....sometimes you have to take things into your own hands.