Sorry we lost our internet all day yesterday. Thanks for all the suggestions. I will try to answer questions.
First an update-The 1 year old hen is still unable to stand or move. Drinking only and very alert-enough to reprimand a chick for stepping on her. LOL. She will not eat  
		
		
	
	
. The younger birds seem much improved (there were two of them). They are moving around but do not stay standing for any great length of time. All are eating and no new ill birds. There is mass confusion regarding hierarchy! 
I don't use any products in our yard. -Now that I think about it the neighbors do though. Crud. Can they get ill if weed products are sprayed - you know via air? Then why only certain birds? The birds in the shed are closer to their yard. We don't have rats or mice so no traps for that. 
re-Food. I was just finishing a bag that was new-bought last week. I had bought two. I brought in the other bag from the car and put it in the plastic bin that night and woke up to find millions of tiny (barely able to see) greyish bugs all over and in the bin. There was none on my other bin of cracked corn that has been open for weeks. I have no idea what they are. Left open to the sun they went away. 
I had cleaned out the coop a week ago and did so again that day. Scrubbed the floor with soap and water and left in the sun all day. Put down new shavings (pine). I carefully looked at old shavings. They were dry except right under the roost area. Nothing unusual. continue to look for strange droppings but nothing looks out of place.  
I do have a neighbor that quit being nice after we bought the birds but really can't get in the yard-have a very tall wooden privacy fence. He is miffed because we can legally have them. He was afraid of noise and smell which I try my best to control both. No roosters but there is some loud egg songs occasionally. We back up to a strip mall which is tons louder than the girls. The only strangers we have had have been landscapers and such in to look at the yard so we can move the shed and build a new coop. My husband was out there with them though. The other side never has complained and most time they are never home.