Have a 5 week old mixed flock (2 columbian wyandotte's, & 2 mixed bantams, and one dominque). Noticed two days ago the dominique was making a little popping noise when breathing. Only loud enough to hear when i would hold her close. At that time she was eating and drinking very well. Today less energy, runny stool with no blood; mostly clear with pale yellow, and really huddling up to the other chicks like she was trying to hide. So...any ideas as to what i could be dealing with? Should I separate her or will that cause undue stress? Is it because she is the only dominique in the flock of five? She was not interested in the broccoli that the other 4 devoured a few hours ago either. All other birds are active and show no signs of distress. Finally...I am new to raising chicks, or at least since i was a kid. Any advice would be greatly appreciated.