I have read nearly every thread I could find on the forum....still do not know what to do. On Tuesday, my friend and I searched out where the rats were coming from. We searched around my neighbor's barn and old sheds that he no longer uses(with his permission). Finally when we were about to give up....my friend spied something at the end of my chicken house. We got down and looked. They are under the hen house! My hen house is a used one we bought from a farmer and is made of double walls of old hickory or locust. It was brought here on a trailer and leveled onto cinder blocks. One end had some loose boards that we never got around to fixing, they went under the chicken house, not into it. The chicken house sits inside a pen with wire fence and HC 3 feet up and a apron going out with 6 in. wide board nailed at the bottom. The rats tunneled under the apron, came up on pen side and then tunneled under the apron surrounding the run. From there I guess they realized the boards were loose and now they are under the hen house. We put out a bait station with Tomcat poison in it. Checked it today, they are nibbling on it. I am SO petrified that I will poison my Great Pyrenees who is doing a bang up job guarding at night(I "was" having a coyote problem but no more!) I bought "One Bite" today but haven't opened it. Should I continue with the poison? We put a bar or two down the tunnels we found too. I thought about hooking the hose up tomorrow and filling the tunnels with water...but what about the poison I put in the tunnels two days ago? No chickens hurt yet....rats are going after the feed that is in feeders in run. I am about at my wit's end. I don't think there is a way for them to get in the chicken house at night...it is pretty tight and windows and ventilation are HC. Sorry this was long...oh, and I am getting a barn cat.