In this photograph you can see several features of the chicks -

In the roof of the mouth of the chick at the top-right you can just make out the rows of papillae either side of the cleft in its upper palate - I hope to get clearer pictures of these as the chicks grow.

In the mouth of the chick at the bottom-right, you can see its triangular tongue.

The chick at the left is displaying it's thumb.