I'm thinking those yearlings are needing a bigger soaking dish. How big are they, about 9 inches? I don't know the sizes of shoe boxes which I think they are soaking in. I would guess at least 10-12 inches though and there's a little room left.
~ These were all hatched in early 2015 and from different clutches, they are all between 7 and 8 inches. We typically see the majority reach 9" in the two to three year range, especially young males.