Don't know how well known this is but please do NOT use AMDRO or most of the fire ant killers that are on the market. They are DEADLY to all birds and therefore chickens. The warning about deadly to birds is in VERY small print on the containers so it's easy to miss. Once they eat even a little bit they are dead within the day. I killed 3 of my favorite girls when I was still new to chickens by using this ant bait. Since it's deadly to all types of birds I personally think it shouldn't even be on the market but a lot of people buy it without realizing they can kill off their songbirds and any other ones including chickens. There are a very few that are safe but make sure to read the containers VERY carefully before you use them.