2 x Silkies same age?

[Tracy the chick]

https://www.backyardchickens.com/forum/uploads/104981_charlie_006.jpg



Hi i have 2 x Silkies Both The same age! but miles apart in height is this normal? Not sure if you can see the picture..

 

[Tracy the chick]

Just let you know the one on left is a gold silkie and the one on right is a white silkie... Both are totally well and eat loads...