Electric fence!!!!!!!!!!
It is always on duty.
You can have 17 shotguns, 13 pistols and 6 tin cans full of rocks, but if you ain't there to use them, then they will protect nothing. The electric fence works when you are at home, it works at night, it works when you are gone, it works all the time.
Dog? Have read a few post about the guard dog, eating the chickens. Besides you don't have time to train a dog, you need protection for your chickens now!!!!!!