I have a 5-day-old buff brahma pullet who has been yawning frequently (~ yawns every 20-30 sec in bouts of 5 yawns or so) this afternoon, and when I picked her up to listen for wheezing (lungs sound clear), she pooped; the feces was runny, bright brown (not bloody), and smelly. She is alert and active, eating, drinking (she has been drinking more than the other two chicks...), and preening, and does not seem uncomfortable. I've set up a large (3' x 2') cardboard box as a brooder; the floor is covered with aspen shavings; the chicks (there are 3 total) are being fed Geeks chick crumble. Is this something serious, or a baby-bug that will pass on its own? How can I treat her? Do I need to separate her from the other two? Thanks!!!