On the second or third day in the brooder I take some dirt out of the run and feed that to them. Just scatter it on that plywood. Then every 4 or 5 days, give them some more dirt. To me, this accomplished three things. It gives them grit. If all they eat is chick fed, they don’t need grit but I think it helps set up their digestive system the way it is supposed to be. Secondly, they get any probiotics the adult chickens have. Third, they are exposed to whatever the adults have as far as diseases so they can start working on flock immunities. I’m specifically thinking of Coccidiosis which lives in the ground. To keep it simple, if you feed them dirt every 4 or 5 days and keep the brooder dry, they should develop the immunity they need in less than three weeks without ever getting sick from it. But if your brooder is wet or you have a really nasty strain, it still might be a problem.
Ridgerunner, I've never had chickens here at our place. This will be my first batch, so would I still need to feed them dirt or not?