One of four babies who are about 2.5 weeks has a bald spot on her head about 1 cm. in diameter. I was spending some quality time with this chick just a couple hours ago and her head was fine, so it must have happened recently. These chicks were hatched together, nothing in their living situation/feed/etc. has changed and all are healthy. The bald spot is just bald. It's not red or bleeding or anything. Is it most likely that another chick pecked at her? Wouldn't it look red? Do I need to separate her? Thanks.