Yesterday am I found one of my 16 hens dead on the floor of the coop. All my hens appear normal and healthy. I thought maybe it was just old age~ This morning I found 2 more dead on the floor. I have not done anything different than I've done for the past 6 yrs. It was very hot the past 2 days but its been hot other summers also. Plenty of clean, cool water etc. always avail. Only difference is that the coop is in a horse pasture and for the first time the horses are not here for the summer, therefore the pasture is really growing. The horses always kept it eaten down in the past. Could the hens have eaten a "bad" weed? Are the eggs I collected this morning safe to eat? Any suggestions??