I tried Amdro years ago but it is made from corn and chickens, goats & other animals really like to eat it. My chickens were eating it as fast as I put it out until I realized why they were following me. None got sick or had any reactions but I haven't used it since.
From the company (BASF), "Amdro uses a
corn grit and
soybean oil base, and must be used within three months after opening to be effective. Amdro has several drawbacks: (1) when it rains, or the bait is moisturized, Amdro loses its effectiveness entirely; (2) insecticide baits tend to be slow working, and take up to a month to be effective; and (3) Amdro cannot be used on food crops.
I have not ever found a cheap, non-poisonous nor home made fire ant treatment. Some things (boiling water, charcoal lighter fluid & matches, propane weed torch) will kill the ants directly contacted but not the colony.
Imported fire ant colonies can have a single queen or multiple queens.
Colonies frequently migrate from one site to another. The queen needs only half a dozen workers to start a new colony. Workers can develop a new mound several hundred feet away from their previous location almost overnight.
I hate the darn things but I have to say, I rarely find them in the chicken pen. The pasture and particularly the fenceline are studded with fire ant mounds.