Rats wiped out my whole grower pen last year. It\'s fairly easy to tell it\'s them, they don\'t even scurry away until you are right there. I had to make 1 by 1/2 inch wire cages for grow pens. The young rats would get in 1 x 2 inch wire. They would also pull chicks through the 1/2 in wire, so I had to make wooden brooders. Rats have been absolutely my worst predator yet. I\'ve had an owl take 3, a weasel took two, a raccoon took one, dogs wiped out a dozen, but the rats did in 100s!