Western Gull - Chicks

I didn't notice the Western Gull chicks at Oregon Islands National Wildlife Refuge at Bandon on the 4th, but the morning of the 5th they were hard to miss. Especially these two on the north side of Middle Coquille Point Rock. At first I just saw the one with Mom (or Dad) standing watch. Then another waddled up the rock next to the first. Lighting was tough with the brightly side lit white birds against the dark rocks, but the top two turned out pretty good.
Most sightings where much more distant on the top of Elephant Rock where I also saw many Common Murres and nesting Brandt's Cormorants.

Western Gull - Webless Feet

While looking through some images of gulls I took at Boiler Bay a week ago from last Friday, I noticed that this one has no webbing between the toes of its feet. You can see a ridge of flesh along the inner sides of the toes were it appears the webbing should have attached.
The gull appears to be a Western. I did some internet research and could not find any mention of a gull without webbed feet or any irregularities. I assume this must be some type of genetic defect.
If anyone knows anything about what may have caused this, let me know.