Depressed or Sick Silkie I just don't know.. Please HELP!!!!

I have one depressed silkie, At first I thought she was Broody. But she is showing signs of depression. We got a new chick 4 weeks ago and another one of our hens has become mama hen to this chick. Our white silkie is spending most of her day in the coop, drooped wings, head down, she comes out for a little while in the morning to eat but then goes back in the coop. My white silkie and this other hen are like sisters and now that the chick is here the other hen is not paying so much attention to my white silkie. My white silkie was my best layer and now she is not laying at all. She is not sick, just very down in the dumps. How do you help a depressed chicken?????

UPDATE: Not sure if she could be sick. She is not acting sick to me. She is coming out of the pen eating and drinking, running around the yard. clucking a lot. She will stay out for about an hour. She is eating strawberries, tomatoes, bread, plus her feed. She has stopped laying eggs it has been a week. I brought her in the house today thinking that she just needs more one on one attention. she has been fine in the house walking around talking to us, coming when we call her name. going in and out of her pen that we set up for her, pooping all over my floors. LOL!!! She is leaving big poops out side, they look normal not wet or runny, no signs of worms. I gave her a bath last week to get the dirt off of her. She is white but she was black before the bath. I usually give her a bath every 2 months so she is use to them. I am not sure if these are signs of her being sick or depressed... I don't know how to get her out of this rut. I really thought it was because of the new chick and she was "odd man out" but now not sure. She is my best layer and stopped laying once we put the chick in the pen full time...