I was going to mention the dander from the new feathers too. It's crazy bad when they're shedding the feather enclosure from new feathers as they grow in. It could of course be the pine shavings as well, but everyone should keep in mind how horrible the dust/dander is if chicks are ordered so they have to be in the house over the winter or early spring! It's enough to give a perfectly non-allergic person fits!
Once they're outside and busy being grown-up chickens, it's unlikely that anyone needs to be inside with them enough to have too much of a problem.