4 wk. old Australorp on hocks too much?...seems weak to walk

[thegreypony]

New to this chicken thing but spent ages in vet med so I'm hoping you folks can help...
Got 9 2 wk. old chicks from breeder couple of weeks ago. This chick has had zero probs but today while at free time (x-pen in yard w/8 yo daughter acting as "rooster/lookout") I noticed she doesn't seem to want to stand and/or walk. She seems to want to lay back on her hocks. I can't find any injury, heat, swelling, etc. She just seems weak. I separated her from the bigger chicks into a brooder with two tinies who were getting crowded out of the feed and she just sits. She'll eat/drink and normal poop but the hock thing is weird.

None of my books point to a disease/disorder that manifests itself this way. I did Terramycin in the water 4 days out of last week. Keep the brooder clean, etc. Thoughts??
TIA

 

[HorseFeathers]

Was it really sunny out? When they sunbathe they just lie on the ground. They can't help it.

 

[thegreypony]

Yes and no as I put the x-pen in mottled light. She fooled around scratching a bit and laying over - normal behavior. But then the flock-ette got spooked by the cordless drill (hubby was doing some work on the hen house) and several scooted away. She stood and then seemed to take these very stilted/stiff and cow hocked steps. I'm finding that the difference in temperament between the 'lorps and the rest of them sometimes throws me off. The one I think is a roo is totally cool about EVERYTHING. He's watchful and curious but stands his ground when anything new is introduced. Maybe this girl was just tired but the change in her walk is what causes me to worry something's wrong...I hate these parts of the learning curve!!