16x16 Run Roof or No Roof Suggestions

[pennhens]

Also, what do folks think of adding pigeon spikes or an electric wire around the top perimeter of the run? This would potentially keep off any climbing predators and allow me to use a lightweight material that wont trap snow.

 

[Seaslug]

I don't know that spikes would keep out predators. You may want to update your location so people know what sort of predators you are dealing with...
I do not regret having 1/2" hardware cloth covering my run. I am not sure why people think that predators do not reach above a certain height. Snakes, lizards and most carnivores can climb, especially when given foot holds like fencing, and obviously birds can fly over fencing. I would have a hard time thinking of a single potential chicken predator that could not climb fencing. I had a dog that could climb our 6' wooden fence by using a nearby tree as a brace for his back. I've personally witnessed foxes, bears, snakes, lizards, raccoons, rats, mice -- even groundhogs and turtles -- climb fences and trees (well, not a turtle climb a vertical tree trunk.)
I do regret not putting a roof over the entire thing, as a wet run is no fun for the birds or me, and it would have been easier to roof without the hardware cloth on.