Am new to chickens. Have recently lost two lovely birds to similar symptoms. It has been hot so suspected it was dehydration but can't be sure. Both hens one 2 year old orpington and a 3 month old black maran became lethagic with their heads and tails down. Would not ea or drink. Would just huddle with their eyes closed feeling bad. Both dued with in 24 hours. Both had bright green runny poop. Any ideas?