I have 12 pullers that are all almost 3 months old. 4 days ago I gave two Polish away to a friend. The next day one Polish is dead (out of my flock). I figured maybe it was a freak thing or it was sad it no longer had one of its "friends", plus I read that polish can drop dead at any time. Well, the next day, another one died (another polish). Then the next day a big, hearty amberlink. I am freaking out. The 2 Polish I gave away are doing fine. I have not noticed any of the pullets coughing, acting sick, etc. They are eating and drinking fine. It is hot here...but it was 100 degrees last week and they were fine. They have been outside for the last month and a half doing fine...segregated from my older girls. All I can think of is coccidiosis, although I haven't really noticed any bloody stools. I wormed them all today and was going to start them on antibiotic treatment in their water. Was also thinking of moving them inside with air conditioning. I checked on them all last night at midnight and they were fine. I switched them back on the medicated grower feed. That's all I can think of that maybe is what caused it. Any other ideas?? They are not vaccinated and are a mix of hatchery and local chicks. My older chickens show no signs of having coccidiosis.