Leg Problems in Multiple 4-6 week old Chicks

[H Diamond]

I need some help from you guys! I have a pen of 4-6 week old chicks. Some I hatched, some I had shipped in. A few days ago one of the youngest CCL ( shipped)chicks started showing signs of leg weakness that progressed to walking on its hocks with wing assistance. Yesterday I had another CCL (same shipment) start showing weakness and it is now walking on hocks. Now this afternoon, I just went out to check and I have a Salmon Favorelle [hatched here from eggs (not mine)] who is starting to show left leg weakness (paralysis?) It seems that they just can't make their legs work right. They will hobble over to the feeder and eat, as well as to the waterer.
I read last night that it could be riboflavin deficiency, so dosed the two from last night with like 200mcg of riboflavin (in the form of b complex) and added some to the water for everyone. This SF I just found was walking completely normal just about 4 hours ago.
Thoughts? I've never had this before, same food, water, management etc as all my chicks get.
These guys are my pen of "I've saved my egg money for 2 years and could finally buy the birds I've always wanted pen" marans, ccl etc, and I can't afford for them to all die. I hate when I don't know how to help my critters :/

 

[Eggcessive]

It does sound like riboflavin deficiency with curled toe paralysis. Leg issues are also very common with incubated chicks from temperature issues. Keep up the riboflavin and other B vitamins. If that is the problem, it should help within a few days to a week.

 

[H Diamond]

Update on these guys if anyone else has this problem. All have made a full recovery except for the first CCL chick that started with these symptoms. All total i had 5 chicks showing signs. All were started on injectable vitamin b complex dosed orally until signs diminished. The ones i caught fast only needed a couple doses. One took several days to recover, one took several weeks, and now has some stunted growth. The worst one is able to walk on it's feet now rather than its hocks, but walks drunk still and has stunted growth. She gets around to the feed and water well, so giving her time to see if it still might correct or if the damage was too severe to correct. Will monitor for quality of life issues for her. All chicks have been switched to non medicated feed and get vitamin tablet in their water (made by manna pro for daily use)