I think I might start recording it, as well as the temperament of the snakes involved. When everyone sheds at once, my female or oldest male are usually the first to go blue, followed a few days later by the younger ones. I don't think they have anything so complicated as an age-based hierarchy or anything, but I don't think it's unreasonable that a very timid snake might be more susceptible to hormonal or other signals than a calmer, more assertive snake.

Of course, my four snakes are in no way a large enough sample group. I guess this means I need to go out and find more garters.