That's true, particularly if the substrate stays wet for any significant length of time. Generally, they do really well (in terms of avoiding respiratory infections, one good measure) with a minimum humidity of about 40% and a max normal humidity of 60%-70%, but unless the humidity is 60% or greater at shed time, they tend to have incomplete sheds which they don't normally have in the wild. Sorry if that's a bit convoluted, but what it really boils down to, I think, is that in the wild, the food is more readily available during the less dry times of the year, and therefore that's when they do more of their eating, growing, and shedding.