This is my first flock. I had 8 pullets and one cockerel until one of the pullets (could have been a cockerel) died yesterday of an unknown illness. She was the only Polish of the bunch. The only other ornamental chick is the bantam cockerel. The Polish chick has always appeared to be the most fragile and was hen pecked by the Easter Egger early on, but that seemed to have mostly resolved since moving into their bigger coop and pen last week. I have never noticed any blood in poop. The dead chick did appear to sneeze every now and then, but that seemed to have resolved as well. However, she was increasingly aloof over the past few days and today I noticed another chick, barred rock, being less energetic and more aloof. Tonight she didn’t get up on the roosts with her friends. I will quarantine her. All the other chicks are happy and active as ever. However, any idea what’s going on? I gave Corid today just in case, but I already did that two weeks ago for five days when the Polish chick seemed to be under the weather at that time (sneeze, puffy eye). I regret not keeping her separated from the flock this whole time. Now I have reason to believe this could be something contagious. The supposed sick chick is eating and drinking and walking, just not as energetically. She has fluffy feathers and a little mohoak, puffy ear muffs and a beard, so it’s hard to tell if her feathers are fluffed up bc she just generally looks fluffy. She looks to be a decent size but could be the feathers. I treated five days of Corid starting two weeks ago and started again today. I started them on a new bag of medicated starter feed a few days ago. Before that they weren’t on medicated feed, but I had been putting a cap full per gallon of brown medication stuff in their water for the past week. Any advice?