This was just in the Chicken Keeping Secrets newsletter I subscribe to:
"How is the best way to kill fire ants around chickens and
chicks?" ~ Judy Goodwin
Hi Judy,
Thanks for the question.
You might recall that we own a pest control company so this
question is right up my husband's alley.
Although there are numerous all natural home remedies touted
across the internet and in books, understand that a large portion
of our income each summer comes from people who have tried all
these home remedies and still have ants.
In other words, I hope you were not looking for a solution that
included sprinkling baking powder inside the ant hill.
My husband's recommendation is Amdro Ant Block.
Make sure to get the Ant Block and not the Fire Ant bait (don't
ask, just trust him on this, the Ant Block is more effective than
the Fire Ant bait).
It is a non-restricted use material available at most hardware
stores.
It is the most effective thing he's seen for fire ants in 20
years in the business.
To be effective it must be used in a particular way; the bait is
sprinkled around the outside of the ant hill, making sure to not
disturb the ants. The ants then pick it up and take it down into
the colony. You cannot put it directly down the ant hill.
This poses a problem if your chickens are free ranging though as
you don't want them to eat the bait.
If the hill(s) are outside an area where you can confine your
flock for 24 hours, you're all set.
Just put out the bait, confine the chickens and within 24 hours
the ants should have removed all the bait.
More often than not, chickens will eat ants, even fire ants.
Based upon some research I did, it seems that most flocks love
them.
However, there was the occasional flock that avoided them. I'm
starting to wonder if avoiding them is a cultural thing (the
culture of the individual flock I mean,) similar to laying eggs
outside a nest box.