Every now and again one of my hens will kinda seperate herself from the flock and sit down and close her eyes and don't want to do anything. I already lost 3 hens from this and 2 are doing it right now. But they have layer pellets,water,scraps,free range sometime,not over crowded,and I bought a bottle of 30 tabs of Manna Pro Life Lytes Mega tabs and they are vitamins and nutrients for chickens in time of stress or heat and I bought it to see it if would help but I bought it yesterday. And I've gave them yogurt before when it happens and they get better than they go back to the same again and one of the hens that's acting this way poops green which means she isn't eating....I take care of my flock and love them to death and I'm tired of losing them and them not feeling there best and I usually know everything there is to know about chickens but this one keeps coming back and I have no idea what to do. I REALLY appreciate whatever you can tell me!!!