what ever floats your boatI was advised to give powder milk sprinkled on feed for chicks with coccidia. Something about the milk does something to the cocc and kills iti.
Humans are the only animal species that drink milk & eats milk products after weaning...so based on that, milk for humans after weaning is also not natural...especially milk not from our mothers.
Chickens are omnivors, they can eat everything...years ago, farmers would fed excess milk from their cows to their chicks during the winter when they couldn't find bugs, etc. to eat. They survived.