Hello, glad to have you join us but so, so sorry about your losses.
I would be concerned enough to pursue having the lost chickens necropsied.
Many states have poultry labs that perform that function with no or minimal cost but you would have had to keep their bodies refrigerated or in an iced cooler to get this done. You can google your state for poultry labs or contact your county agent for advice.
Also make sure to inspect your feed for mold or spoilage, if you have just opened a new bag of feed - replace it with new. Check their water supply for anything unusual. Inspect the coop/run area or foraging areas for anything that may explain this.
It is hard to lose any flock member, but without any sign of illness, injury or warning, I would find it devastating. It is best to find out what happened to try to protect the remaining flock.
Again, so sorry about your losses
and hope the rest of the flock don't have any issues.
