My 3 week old chick has a big bald mass? She was bald in that spot when we got her from the hatchery but it has gotten worse. She only eats the starter chick feed. She gets her hydro-hen 3 in 1 with a splash of ACV. She is very active like nothing is wrong, she isn’t bullied by the others. She does have the pine shaving in the brooder box. Heat lamp is set for the ones a week older (75-80) but we have the ecoglow for the 3 week old ones to go under if needed. I don’t know her breed, it was just a mix of 10. She is getting some of her big girl feathers in but nothing in those areas.First time owner of them. I don’t know what to do for her, it breaks my heart. They are for egg laying only. I took some photos to help. Any thoughts?