I would wonder if the bag of feed you are using is old, or got too hot...I put the chicks in something larger. They had outgrown the plastic storage container brooder. I have at least one that the toes have more recently curled sideways. No, they're not broken. No, they weren't curled like that the first week, and a half after hatching, so I think it's a bit late in the game to put a boot on it. No, the toes are not broken. Yes, they are eating good feed. Nutrena chick starter. I don't like their feather quality either. I've got one that has very little down, so it looks sort of bald, but it does have some of it's feathers trying to come in. Tomorrow, I'm going to mix some Mana Pro Gamebird/Showbird feed into their Chick starter feed. It's got a very high protein content, so boosting their protein may help. I'm not holding out any great hope for them though. They're just very poor quality birds.
Sounds like a lack of vitamins. I would give them the vitamins suggested to fix wry neck (is that E?) As well as nutritional yeast.