I brought home two 3-week old chicks from Agway a few days ago and as soon as I got them in the brooder, I noticed they had bald spots. They are completely quarantined from the rest of my flock, but I'm not totally sure what I'm dealing with here. Their vents are completely clear and healthy looking, and in these bald spots I'm not able to see anything crawling around. They ARE, however, acting "itchy" and preening the base of their wing feathers constantly. Should I just go ahead and treat them with poultry dust to be safe?