How many chickens did the bear kill? You said you moved the chickens to the farm, so I wasn't sure.
I can think of a few ways to stop a bear. You could have a couple of large dogs to keep the bear out of your backyard. That is probably the easiest way. You could put boards with nails in them along the outside of the fence to keep the bear out of your yard. Although, a wondering dog may step on the nails also. The third way to stop a bear is to shoot it. It is legal to shoot an animal if you catch it trying to kill your chickens or trying to attack your family. I can assure you that if a bear came to my back porch I would shoot it.