Help Needed. Young Chick not walking

June is laying down on left


June is standing on the right.. notice how she stands on her own feet.


Using the attached photos, This is June, she is 12 weeks. About 6 days ago she was out foraging with the other girls, looking pretty good, however I noticed she seemed to need to lay down a lot. Didn't think much of it at that time. By (this last) Tuesday while all were in the run, when she walked she walked low to the ground almost on her hocks, then like it wore her out she would lay down. Then list to the side. Sometimes throwing a wing out as if to steady herself. When walking she crosses her legs at each step then while standing she stands on her feet legs crossed. She desperately wants to keep up with the others and did her best but would just lay down once she caught up. Sometimes she would flap her wings and try running in a funny kinda walk run to catch up. By Thursday She spent most of the time laying down. I picked her up, with out a fuss, and my hubby checked her over for injuries, noting her keel stuck out. He caught one of the other girls and said that one was about the same. We figure its just cuz the are young and haven't put on a lot of meat yet? After spending much time on the internet trying to figure out what might be wrong, we started treating all for cocci just encase. We ruled out Mareks as she is alert, eyes bright, eats and drinks. Although we noticed by Thursday night the others kinda push in to eat and she doesn't have the strength to push in too so ends up laying down while they ate. We put a second feeder in on the ground so she could eat laying down and lowered the water jug so she could reach that also laying down. We thought maybe an internal parasite and treated them all with corrid. We didn't separate her as it seemed to really upset her. And in the coop she would sleep huddled in with the rest of the girls. They too seem to want to stay with her.
We found a mash recipe online with plain yogurt, baby applesauce, hard boiled egg yolk and pelletized feed. Friday (yesterday) I was able to walk up to her and pick her up with out a ruckus or a sqwak. As I held her she seemed to calm down and tried to go to sleep. We didn't have all the ingredients but my hubby made up a version with plain yogurt, minced apple and some organic feed. Earlier- he had put it out and the other girls gobbled it up but she didn't get any. So while I was holding her, he went and made up some more and I was able to hold a small bowl for her while she heartily devoured it, followed by many drinks of water. after that she was ready to sleep. (we were building a feed shed, and the noise kept waking her). Her pooh is normal. (She pooped on me twice) We decided last night to put her in a rubber tub and bring her in. Put her in a back dark room by 8PM and she went right to sleep. She slept until 7:20 this morning. Nothing has changed. She still doesn't stand she lists to one side like her equilibrium is off. and when my hubby took her out side he said her left leg seems to cause her discomfort.. (Since feeding her this mash, her pooh has a strong oder now). ANY ideas we are out of them and don't know what more we can do or if we are doing the right thing.. she is currently next to me in her tub while I write this.

She may have a vitamin deficiency, a leg bone deformity that is getting worse, a slipped tendon, or she could have Mareks. Some chickens can be perfectly alert, and eat and drink with Mareks. I would probably do some research on some of the tendon and bone issues such as tibial dyschondroplasia or rotated tibia which are more common in meat chickens, but still show up in layers. Do you notice any swelling in the leg above the hock? I would keep her with her flock, and treat them all with a good poultry vitamin that also contains trace minerals.
https://sites.google.com/a/poultrypedia.com/poultrypedia/poultry-podiatry
http://www.thepoultrysite.com/publications/6/diseases-of-poultry/220/slipped-tendon-perosis
https://aaap.memberclicks.net/assets/musculoskeletal preview.pdf
http://ps.oxfordjournals.org/content/79/7/982.full.pdf

Thank you for responding,
Will spend time looking at your links and studying up on leg/tendon issues. There doesnt appear to be any swelling. One thing I forgot to mention was how pale her legs were a few days ago, but yesterday they have gotten back to a yellowish color. I just looked in on her and she was standing and stretching, but laid back down.

As far as vitamins go.. We have her on a high quality feed that is an all
Baxter Barn Quality feed goes beyond the average bag of feed including but not limited to:

UPDATE: Sadly, we had to put June down this afternoon. She just wasn't getting any better despite everything we did to help her.

Sorry for your loss. If a vitamin deficiency is even suspected for certain leg problems, I would give a good poultry vitamin supplement, just in case the feed has sat on the shelf a bit, or the vitamins were omitted accidentally. Many of these deficiencies, though, have been in the parent stock. The best response to vitamin therapy is in early riboflavin deficiency or in wry neck or encephalomalacia.

Thank you Eggcessive for all your info. The other five are doing great and are healthy and growing as they should be. We did get vitamins as suggested, but she just didnt respond to any treatment. When with the others she as noticeably smaller and thinner, where before she was growing at the same rate. In the last couple days when she would try standing she had started falling face first. Yesterday my husband said she was not to suffer anymore.

Antibiotics are used in prevention of bacterial respiratory diseases spreading in a flock (or culled.) Vitamin C accomplishes the same thing against bacterial and viral diseases, in which antibiotics have no effect against virusus. Vitamin C is a preventative, no resistance/no withdrawal to vitamin C as with antibiotics. However the results are the same when it comes to treatment with vitamin C as with antibiotics; in poultry, surviving birds remain carriers for life for most respiratory diseases.
Scroll down to "Functions," paragraph #2 "Immune System."
http://www.poulvet.com/poultry/articles/vitaminc23-1-2011.php
As far as soap goes and as far as I know; soapy water was used to worm poultry and hogs way back when. I dont know about its effect internally against diseases.
Today we have Oxine to eliminate bacterial, viral, and fungal problems in poultry along with the myriad of medications to treat sick birds.