I worked with pheasants on a larger scale. I use to work for the IL DNR at a Game Propagation Farm where we raised in excess of 40,000 pheasants for breeding stock and state hunting preserves. We had approximately 1000-1500 pheasants per pen with (40) 1-acre pens that were fully enclosed with a hot wire. The pheasants really needs some cover in the pens, so we allowed the Giant Ragweed to grow to about 6-7' tall then we would send a crew into the pen and break the ragweed off to keep it from getting too tall. This provided both shade and cover.
We had to put blinders on the chicks, and kept them in heated brooding houses until they were old enough to go outside. But they kept the blinders on until the day they were going to be shipped out. We expected casualties from the pheasants flushing and flying into post, or hawk and owls flushing the birds and grabbing them through the netting. I would definitely add a hot wire around the base, keep them partially shaded, and protect them from overhead predators.