I had a link to a bear banger description in this thread from last summer (the link is on page 2 of the thread):
https://www.backyardchickens.com/forum/viewtopic.php?id=92682
http://www.ursusinternational.org/en/bangers.html
In Canada, you can buy bear bangers that you use in a standard shot...
We have bears in the yard every year and I agree that an electric fence would be beneficial. Our coop has several locks on it and they are used every night.
We also have bear bangers for our shotgun and use them when the bears come in the yard. We live rurally, but not far enough from all...