Necessary? Nope. It's mainly to provide some climate protection and maybe a bit of predator protection but a lot of people have uncovered or unroofed runs.My question to those who asked about the cover. Is it absolutely necessary?
Snow would probably be a concern (if the run is snowed in, the chickens aren't likely to want to use it) however snow build up on a tarp or even on wire (depending on type/amount of snow that can be an issue) can be equally problematic.
That can help teach them the coop is home, but they'll still need to be trained to use the ramp as that's not a natural thing for them. If the ramp is steep (greater than... 35-40 degree angle or so) propping up the floor end on a cinder block or something similar to reduce the angle will help.BTW, the girls spent their first day and night yesterday in the coop/run. Happy as clams. They're still not sure how to use the ramp to get back in the coop, so we have to wrangle them in at night. It's supposed to go back into the 70s later this week, so if they still don't get coop = home, I will keep them in there for a couple of days when's it's cooler, as I've read this is how to teach them to go back to the coop, thoughts?