looks sick

[jotee]

I have recently ( one week ago) moved my chicks to their coop. They have access to a heat lamp and all in all looked great until today. The one chick that is very friendly is super quite today. She is under the light all the time. There is no runny stool and she ate the treat food (oatmeal,flax.sunflower seeds) I gave her. Only change was yesterday when I let them outside for an hour to forage…Any thoughts, anyone??? Can I help this chick if she is sick???? Thanks...