Wings feathers not growing in?

[Namaste Mama]

I have a banty thats about 2 1/2 weeks old and her wing feathers are barely coming in. what she dose has has little lines through the feathers where parts didn't grown in. She's not growing like her sibling is and is about 1/2 the size of the other one. What could cause this? Is there anything I can do?:|

 

[bheila]

I hatched a blue laced gold wyandotte that was the same way. It was the strangest thing. Mine only had about half it's feathers. He looked sickly. He also chirped all of the time 24hrs a day for the first 3 weeks of his life. He finally grew all of his feathers by the time he was 2 months old.