Wow! I give mine 16% layer pellets , fresh water, froz veg treats and soldier worms. Whenever I get addition to flock I treat with 1 ml liquid ivermectin on the back of neck (topical) takes care of any parasites.
Built my own coop and yard.
Sorry for your trouble. University of Arkansas had free online chicken course that helped me. I use liquid ivermectin to treat for parasites. Blessed with healthy girls so far