Possible Splayed Legs in Almost-Pullet-Aged Chicks

[ChickenBoo]

We have chicks who are almost fully feathered. We just moved them to an outdoor grassy enclosure this week. One of the hens just developed what appears to be splayed legs. Both of her legs are splayed & she's walking (when she's walking) on her "heels". Is it common for this to happen in chicks who are fully feathered? There doesn't seem to be any noticeable disease. Can I bind her legs & fix the splay like I would in smaller chicks? Any help would be greatly appreciated. These are my first set of White Rocks & I desperately want to integrate them into my flock. Thanks in advance.

 

[ChickenBoo]

Upon closer inspection we think the problem is slipped achilles on both legs (if https://sites.google.com/a/poultrypedia.com/poultrypedia/poultry-podiatry is correct, it is not common to happen in both legs). Anyhoo,we've put her in a sling to keep her weight off her legs until we can get her to the bird clinic on Monday.