The chicks are starting to look more like pullets (per www.dictionary.com, a pullet is a young hen, less than one year old.) Hope is even beginning to show signs of developing a comb.
Just as there are many breeds of chickens, there are different types of combs (http://www.backyardchickens.com/web/viewblog.php?id=9280 provides an overview)
Why do chickens have combs? Scientists suggest that the primary function of a chicken’s comb is to help keep them cool, as chickens do not sweat and cannot pant like dogs do to cool themselves. Blood circulates in the dense networks of blood vessels from the chicken’s comb to its wattles. This provides the comb its deep red color and allows the blood to be cooled by the air before traveling to other parts of the bird’s body.
Here’s what Hope’s comb will look like when she’s full-grown: