The weather has been cold and we have had a heavy snow. I let the guineas out by choice through a little door -- over the last week found two grown guineas dead on the ground inside the coop. I have no idea why. There are no marks. They are full grown -- or closely anyhow, born in April. There have been no signs of illness as far as I can tell. I have gone down from 26 to 23 (one just disappeared). Is there any illness that comes on quick and just kills them? They are active, speaking, flying, walking, by all appearances.. I have two heat bulbs on for them in their coop. Water on a water heater available at all times and a layer feed available for them. They get daily scoops of millet thrown on the ground in the coop.