I started this spring with 15 Silkies (chicks) and I am now down to 8. Not a single one has been lost to predators. They all just either drop dead, or sit in a corner of the coop for a few days and then drop dead. Not a mark on them. I am positive it's not predators. I am stumped. We never lose a bunch at once; rather we lose about one a month. My remaining 8 are healthy and active but so were the others before they dropped dead. What can I do? I do not think it is the feed as I changed suppliers, worrying about that very thing. Is there some disease that would cause this? I wrote off the first 3-4 losses as a normal part of chicken keeping, but now I feel like it's getting ridiculous. I am going to have to order new chicks in the spring. But if it's a disease I don't want to spread it to them. Thank you for any and all advice.