I have lost 3 4 month old polish/sultan cross chicks to whatever this is. They are fine during the day and than I found #1 dead Tuesday morning, no sings of anything. Wensday moring, #2 same thing. Yesterday morning I found # 3 dead with a puffy face on one side (side on floor of coop) and what felt like a broken neck near the head. Today # 4 is alive but both sides of face around eyes is swollen/ puffy. The chick is sitting there not wanting to go out for free range or anything. I have other breeds of chicks in with these and they are fine (for the mintue). What could this be and how do I fix it? Thanks for any and all help.