3-4 week chick not growing as fast, leans over and flutters when standing

[MAnRJnTXsmom]

We have 6 3-4 week chicks and most are doing fine. One sweet one, always the smallest but also hatched the last, seems to not be growing its feathers as much/getting as fluffy as the others and sometimes when it stands, especially if we've taken it out of the cage and put it on a non-wire surface, flutters and lays to the side. It also seems like its sitting in the cage more than the others. I suspect its not eating enough but it also may be injured. Any thoughts on what to do. It can walk in the cage but I feel like its sitting/laying more than the others.
We are worried.

 

[Eggcessive]

Many chicks will grow their feathers in at different rates, but I would give it PolyViSol baby vitamins 1-2 drops daily, and chopped up scrambles eggs for extra protein. Just hold it and let it eat as much of the eggs as it wants out of your hand.

 

[MAnRJnTXsmom]

is it weird that it seems to be stretching its leg out when laying down? its only one side so I'm not thinking spraddle but I'm totally a newbie here. I just worry that its in pain w/ its leg or wing.