We have not seen any black bears in our yard but a bear has been roaming the area and apparently has a taste for chickens. He has attacked at least three chicken coops in the last few nights. My sister just texted me to tell me that they woke up to find their fence had been knocked down and their coop had been torn open and she lost three out of four of her chickens. My chickens are in a mobile tractor. It is pretty secure but this is a bear were talking about. What can I do to protect my chickens?