Hi Grace AK, Eagle River is a beautiful place, but you definately need to plan for the preditors. Electric Fence should help with the bears, but I am not sure about it being on the ground...will they dig or climb over the top? And did you mention having a top on the pen?
I think the rooster will only make noise, as will the hens if they are in danger. A neighbor's dog caught and carried off our rooster one year. Of course, it was not a fighting chicken, but then you would have trouble with it attacking people if it was a fighter. As for an older bear, I don't think that would stop him if he could get at the chickens.
All you can do is try and see what works. Have fun with the project.