What would be a good solution to keep predators from climbing on top of this enclosure?

[chickensahoy96]

My suggestion would be use metal roofing panels supported on purlins and rafters with a very thin sheet of insulation between the purlins and the metal. I would not go with the clear panels for reasons already mentioned. With insulation underneath a solid metal roof you won't fry your chickens, shade will be provided and insulation keeps condensation from dripping. You could remove the netting, use metal roof on half of the run roof, and hardware cloth on the other half. With a roof modification you might consider increasing at least some of the roof to "people walk-in height", too.

What about translucent white PC roofing? It allows some light in which is important for chickens to be able to lay eggs and also sterilize the floor, but should keep the temps down. It is actually out of stock but I am considering special ordering it. Maybe there is a reason it for that?