Do some come with inverted wings??

[myboyjack]

I know I'm still learning, but one of my younger ones just isn't developing her wings. It's like they're inverted. Other than that, her activities are normal. Her sister is growing normally, but it's like she doesn't have wings and she's 3 weeks (at least) now. Any ideas?
Thanks in advanced. I would be so lost without this site. You guys are so very helpful.