If you see them in the day your overrun. Shooting them with a pellet gun is good sport but your have a serious problem and it won't put a dent in them. You have 100's of rats. Your only means to take care of it at this stage is to use poison. Chunx poison not pellets and use a tamper proof bait box. I keep one right in the run at all times.I'm having a rat problem. I've tried all humane ways to catch them but they are too smart, So, we are now baiting the front gate to run and my nephew is shooting them with a pellet gun. Hope my neighbors understand. The pellet gun's not too noisy.