As someone else suggested, skip the other nonsense and go right for hot-wire. Once bears learn where a free meal is, they will be back. No amount of noise, scent-deterrents (The ammonia thing is a myth. Only thing dousing the garbage cans with it will teach them is the ammonia smell maybe means food.), or dogs will prevent a truly determined bear. Worse, in letting this situation persist, you're likely letting a mama bear teach her cubs what is acceptable behavior. Get the hotwire up before they learn where the food is, kill your birds, and you start breeding a generation of bears that knows where the easy, human-provided grub can be found.
Problem bears for me have coincided rather nicely with hunting season for them. I make black-bear tacos that are known to cause fights for invitations to dinner. If push comes to shove, it is an option. Buying a tag is within the realm of possibilities.
Feeding stations are perhaps the worst idea I've ever heard for bears. Any artificial feed is bad for them, and it only teaches them food comes from people. It also concentrates bears artificially in a given area. A big boar bear will eat a small sow bear or cubs given the opportunity. How'd you like to be the person living next to a feeding station with a chicken run? Considering Californias bear population is booming, there really isn't a need to feed them. Bears are anything but stupid, and they are great opportunists. They will fare just fine after the fire without help from anyone, just like after the 2008 Redding Fire-Blitz.