Yesterday I noticed our almost 5 mo old beloved Brahma Plinky laying in the corner of the covered run while the others were outside doing normal chicken things. I went out to see if she was ok and she got up and started moving around normally. Today she is obviously sluggish, keeping apart from the other three. I topped off their feed and gave them their treat balls with feed and a few meal worms inside which normally gets her all excited, but she jusst gave the feed a few pecks then lay down and PUT HER HEAD UNDER HER WING! Obviously something is wrong. I picked her up and she feels very light. Her crop was empty (though last night it was full). The other three (other breeds) have all started laying eggs; I know Brahmas develop more slowly. Where do I start to unravel this mystery and help her?