Hi everyone! I have three three-week-old chicks in the brooder at the moment. One of them seems to be sick. It keeps opening and closing its mouth, and there seems to be mucus around its nose and in its mouth. Its feathers are growing increasingly scruffy looking, and it isn't moving much. Yesterday, it wouldn't even peep. Today, it is making noise, though a minimal amount. I've hatched chicks before, and have encountered nothing like this. I have raised its mother and father, and they are both very healthy birds. Is there anything I can do to help this poor little chick?