Lavender Orpington - Lazy, or something wrong with legs?

[Goskeaton]

Hi folks--

I have a lovely 11-week old Lavender Orpington pullet (Princess Kay).

She gave me a bit of a scare early on when she was just a week or two old, not seeming able to stand for more than a minute at a time. I splinted her for splay leg, as well as gave her extra supplements (poultry cell, poultry booster). She did perk up and seemed much more mobile. But I have been noticing that she seems to lie down much more than her flockmates. She'll be up and wandering around with the others, then will lie down. Her sisters will oftentimes lie down with her for a while, then get back up and continue scraping around.
I would say this has been an ongoing issue for the last several weeks-- as we've been transitioning the smaller girls from the brooder to out into the run with our other chickens, I was hoping that maybe being able to stretch her legs and build up muscle would help resolve her issues, but that has so far not proven to be the case.

She does also seem a bit wobbly when standing/walking around. Her gait is just a bit unusual. Her legs seem like they are a bit close together when standing, and her legs seem to sway way out when running (it's very silly and very cute). She also tends to wobble a bit when standing still, which can be viewed in this video:

>Link to a video of her standing and swaying<
(If this link doesn't work, please let me know)

Other potentially useful information:
My pullets are on medicated starter feed
She eats and drinks normally, and seems to be otherwise healthy.
She can roost just fine, has no issues balancing on a bar.
The bottoms of her feet seem fine, there's no sign of any bumble.

I guess my questions are these:
What could be causing this? She's been vaccinated for Marek's, so I don't suspect that as an issue. Could it be a slipped tendon?
Should I continue mixing poultry booster into these pullets' food, since it seemed to give her some help before?
If it is a vitamin deficiency, will I need to continue supplementing for her whole life? How does a chicken acquire a vitamin deficiency?

If anyone has any insight, I would appreciate it! I can provide pictures of legs/feet if need be as well-- these 3 pullets have been snuggly and incredibly tolerant of being touched.

We're new to chickens as of this summer, so still figuring things out. Thanks!

 

[coach723]

Pictures of the legs and feet would be good, I'm wondering if bone formation looks normal or not. Seeing her run would be good too, if you can manage that.
I would give her 1/2 of a b complex or super b complex tablet or capsule once a day, see if it helps. Human ones, any pharmacy or walmart, brand doesn't matter. Since she's been on medicated chick starter, it's possible that the amprolium in it has affected her thiamine levels, and that can cause odd neuro muscular symptoms. The B's are very safe, no worries of too much. If it's a deficiency, then often once you get it reversed, they are able to maintain it normally after that.

 

[Goskeaton]

Pictures of the legs and feet would be good, I'm wondering if bone formation looks normal or not. Seeing her run would be good too, if you can manage that.
I would give her 1/2 of a b complex or super b complex tablet or capsule once a day, see if it helps. Human ones, any pharmacy or walmart, brand doesn't matter. Since she's been on medicated chick starter, it's possible that the amprolium in it has affected her thiamine levels, and that can cause odd neuro muscular symptoms. The B's are very safe, no worries of too much. If it's a deficiency, then often once you get it reversed, they are able to maintain it normally after that.

Here are a couple photos of her feet--

I feel like it seems like there's just a lot of extra padding or loose skin around the bottoms of her feet, not sure what that implies

Her legs have always looked thick to me-- that and a quick-developing comb made me worried she was a cockerel, initially.

Here is the best video of her gait I got tonight-- >Video<
I'll try and get a better video some point soon, I understand this one isn't the best.

Any thoughts? Thanks!

 

[coach723]

Can't really tell anything from the video, but the other picture the legs and feet look pretty normal. Looks like some slight webbing of the toes that may be genetic, would be interesting to know what the parents feet looked like. But that really shouldn't be an issue. Some birds have more padding than others. And thick legs can sometimes indicate a cockerel, but not always. I hatched a chick this spring, a blue rock/EE mix (mixes can fool you) that was a big chick and had massive legs, I was pretty sure it was going to be a cockerel. Nope, just a big pullet with big legs. Another chick that was similar, same mix, is a cockerel, and a third was much smaller and a pullet. The roo they are from is also a pretty large roo so he passed on his traits, though they got the coloring from the blue rock.
The comb and wattles do look large and red in the first picture, for 11 weeks, but I don't see any obvious male feathering yet. I've not had any orpingtons so have no personal experience with how fast or slow they mature. I have some breeds that mature pretty early (I've had fayoumi's crowing at 4-5 weeks), and some that mature much slower, and even in the same breed it can vary bird to bird. Time will tell!
I hope the vitamins make a difference.