I have had my chickens and ducks for two years. This year is our coldest winter so far with them. I have noticed that I have a lot of burrows going under my coops and cinderblocks. We today let the birds wonder the yard! We used a smoke rat bomb that is suppose to kill them. We found like 8 entries and exits. How else can I get rid of these pesky rodents! My chickens and ducks roam around the yard in the pen where there coops are inside the penned in area,....please help! I don't want to use poison since my birds roam around!