I've been waging war on the rats coming into the chicken run and some are so bold as to even be out in late afternoon. I've used snap traps, plaster balls, an electronic trap and a live trap with varyiing results. I don't leave food out in the run and I mix chili powder with their food in the coop (and it is raised off the floor). I am still getting rats, however, and am thinking I need to dig hardware cloth into the ground close to the inner perimeter to stop their getting in. I already have two feet of it going up the outside of the run and two feet going out but they tunnel underneath. So, my question is, how deep do I need to go to discourage the typical rat? Three feet, four feet? Please don't say any deeper than that because I don't think I have the energy to dig that deep!