Young flock of Buff Orps. About 7 mos old, Just started laying about 2 months ago. 6 hens, 1 rooster and an old red Sex Link that no longer gives eggs. They have been healthy and laying. Just yesterday I got 5 eggs. Everything looked normal yesterday when I put them up for the evening.The normal routine is : they are in the pen until about noon and everybody has finished laying then they are let out into the yard (one acre that they share with the goats) until close to dusk. They have access to a feeder of Purina layer, and fresh water. Today I go to let them into the yard and only one BO hen, the RSL and Roo are in the pen and wanting out. The other 5 BO hens are in the coop, feathers all over the coop and they are barely responsive to me being there and messing with them. They are laying on the ground and will not get up. Looking all frumpy feathered, eyes closed but breathing. Opening the eyes when I have contact with them but closing when I quit. Can't find any trauma indication, no blood, scratches, missing patches of feathers. Just the lots of feathers in the coop. The only other thing I can think of as out of the ordinary is that I gave them about 1/2 gallon of fresh goats milk yesterday. First time I have given it to them. But I drank some of the same milk with no ill effects. Temperature today is in the low 80's so that should not be a factor. I am at a loss as to what may be suddenly going on and desperately seeking answers. Anybody out there have any suggestions?