Talking about tin.....I have 2 chain link dog pens that house my chickens. One is 12' x 12' and the other one is 12' x 7'-both are 6' tall. I have tin laid over the tops of these pens to keep critters & weather out BUT-there are spaces that small things could crawl into the pens under then tin, so, how do I seal those places off to keep snakes, or small predators out? I'm not a carpenter and not too handy with tools but probably could do simple stuff to make the pens safer if I knew what to do. Can ya'all help with some ideas?