Need advice HELP sick chickens

[Lovely Birds]

Well first I would like to say that I have raised 100's of chicks to chickens and none have died so I am at a lost. I had 5 in 1 coop. I bought 4 of the 5 chickens from a breeder; 3 were purebred ameraucana's, and 1 is a blue laced red Wyandotte. My other one I bought from a feed store she is a Dominique. So I lost my first ameraucana at 3 months old. She seemed to be growing, but felt pretty skinny like she wasn't putting weight on, my second I lost at 4 months old she also seemed to be growing but very slow and she also felt very thin. The other 3 seem to be healthy up until now. My last ameraucana seems healthy same with the Wyandotte. But now my Dominique seems sick. Very lazy, not active, and I look at her but and looked like her poop was not right. FWI my birds always have fresh water and food at all times, they also have a coop with heat in it, get to free range. Knowing all that what do you think it could be? My Dominique didn't seem sick until I started letting it out all of the time also. Should I try antibiotics? Could it be worms? Also does anyone else have problems raising ameraucana's not Easter eggers, but true ameraucana's.

 

[Eggcessive]

Coccidiosis, worms, mites, egg binding, impacted crop, enteritis, and other problems can cause illness, Specific symptoms would be more helpful--the color and consistency of their poops, if they are huddling or puffed up, and respiratory symptoms, would be good to note.

 

[Lovely Birds]

I thought it could be all those things to. She was lethargic with green poop not very runny though. Don't think its impacted, pendulous, or sour crop. I thought it could be worms, but I am thinking its coccidiosis. Really not sure though. She is puffed up also. Those are the only symptoms.