I have fond memories of running barefoot from end of school to beginning of school during my young childhood. Never had a single infected cut, ingrown toenail, sore feet or any other problem until I had to wear shoes year around.
As far as chickens and vermin: In the 20 years we lived here (only the last one with hens), I always knew we had rats, snakes, raccoons, possums, coyotes, etc. So I keep the food well secured, as I do the garbage can.
And you should see what the hens do to the fire ant hills! OMG! Better than any chemical!
But you need to be comfortable! I'm sure there is some real research for possible things to catch from chickens or chicken poop, and if that is any worse than, as stated previously, the wild birds pooping in your yard.
Back in my barefoot days, every day ended with a soak in a hot soapy tub to get off all the grime from a day of adventures. A tub soak is great for all sorts of abrasions. I wish you well.