What is wrong with my ducklings leg?

[ik]

i just saw him running away in a weird way when i come by the brooder. he/she is a little over 1 week mabye 1-3 days.
after 1 week i moved them to a bigger brooder.With newpapers for the first few days.
what could this be and could it be fixed?
is it spradle leg, slipped talon, vitam diftionce.
i have another duckling and 7 chicks with him.
everyone else is fine.
any ideas please help.

 

[Birdcrazy]

That does not look good at all

He wasn't born with it 'cause you would of noticed it? Does it hurt him to try stretch it out normally? If he was born with it I'm pretty sure there are ways to correct it
I hope he's going to be ok

 

[ik]

i dont think it hurts him he runs away when i come by him and gets food and water fine.
im new to chicken and duck kepping.
and he wasnt born with it.