Leghorn Chicks having trouble standing and walking

[BigSkyFarm]

I have 2 leghorn chicks I am raising to add to my flock. They are about 10 weeks old. These chicks have grown at incredible rate. They are twice the size of the other breed of chicks I am raising. Their feet are huge. They just cant stand well or walk easily. They just sit down and eat and drink. Otherwise they look healthy.
Is this normal?

I have raised a lot hens, this is the first I have seen this.

 

[mamajos]

Can you add a picture of them?