Besides the red in the wattles and comb, look for "engorging". Combs of infertile hens and pullets are dry and shriveled. As the hormones surge, the tissue becomes engorged with new blood and it swells, sort of like a wet sponge.
So, look for the combs to look larger and more erect in addition to being a deep red color, minus the dry appearance.
So, look for the combs to look larger and more erect in addition to being a deep red color, minus the dry appearance.