Most of the south is all wrong, environmentally speaking, for pheasants. As is most of New England and the Mid-Atlantic. Look at the native habitat of these birds. Pheasants are native to the moderately high elevation grasslands of Asia. They originally hail from countries like China, Mongolia, parts of Russia and other former Soviet Republics like Kazakhastan, Korea, and Japan. They live in temperate climates, which are not extremely hot and not extremely cold for long periods of time. The first pheasants appeared in the US in the late mid-1800's and were first introduced to the river valleys of Oregon. They spread east from there.
Foxes, skunks, raccoons, coyotes, Crows, magpies, ravens, as well as raptors all do a number on pheasant nests and brood numbers. But given the right climate with the right amounts of feed and cover, in proximity to water and hide/roosting cover, they do alright. The betterthe cover, the more successful they are at avoiding the predators.