Don't worry, I've had this happen from time to time with both chickens and ducks. Sometimes they manage to come out still in the posture they were in the egg... curled up.
I'm not sure why, it may be they just came a little early or got out too easy without yet forcing enough use of their muscles, were weak or just runts.
The good news is, every time I have had this happen, after struggling to get up and around for some time they always managed to straighten out and end up fine. I've never had to nurse one back, it took care of itself. I do leave them in the bator until they are straight and walking though. They may chill more easily or use too much needed energy trying to stay warm otherwise, but I'm just guessing.
I would not cull him and just wait it out, but keep him extra warm inside the incubator. I'm sure a little dip of b vitamin or sugar water wouldn't hurt and may help give it the energy it needs, I personally would leave it alone so as not to add any stress to it's situation.
I'm not sure why, it may be they just came a little early or got out too easy without yet forcing enough use of their muscles, were weak or just runts.
I would not cull him and just wait it out, but keep him extra warm inside the incubator. I'm sure a little dip of b vitamin or sugar water wouldn't hurt and may help give it the energy it needs, I personally would leave it alone so as not to add any stress to it's situation.
over the years I have had this happen. I usually give them a little extra warmth and alone time. Most of the time in a couple of days they are up and running with the rest.