Flock size???
and your ventilation is inadequate. Problem with pre-built sheds, they are intended to keep the outside out, and have almost no consideration for venting interior moisture sources - like the breath and droppings of your little dinosaurs. Temperature gradients just aggravate that. In a wooden shed, the first answer is to cut larger openings...
Assuming you don't want to do that in your plastic shed, can you remove the sky lights, reattach them on the top of the roof, but gapped/spaced to allow additional airflow without making that a source for rainwater entry?
You may need to construct crickets, as you would on the high side of a chimney, to divert water.
Alternatively, you could consider placing roof vents (turbine) in two of those skylights, or other designs whether solar powered or otherwise (solar of course won't work overnight, when covered by snow, etc - good for forcing air during hot days, not so great otherwise. If you have power in the shed, then of course you have lots of options.