Red-bellied hens are often thought of more "drab" in colour comparatively to the males, with their bright orange belly, but I think drab is inappropriate. Their colouring is just more subtle, and varies more from individual to individual, unlike the males.
Some hens have more grey on their bellies, some have more orange and some have more green. I find Pixel has a nice balance of all three. But the true splash of colours happens under her tail!