Pheasants need timely spring/summer rains and undisturbed nesting cover more than grain.
Yes ringneck pheasants will reproduce in southern Texas. Rain is very important for both quail and pheasants because the new green vegetative growth is full of nutrients. And healthy green growth produces fat high protein insects. All of that helps the hens to lay a healthy bunch of eggs and hatch a bunch of healthy chicks.
And if it continues to rain in the summer (with healthy green vegetation and insects) the hen needs to stay fat to produce more eggs (100 egg follicles in hens) the hen can easily lay another clutch of eggs and have a second hatch. So timely rain is big time need for game birds in Texas. They will not drown but in a hot summer (like 2011 the chicks will die of dehydration) poor food supply because of poor insect production because of the drought.
But not with the tame fat 60 or 70 generations (of living in the pen) pen raised pheasants. You need to release the wild more alert strains of (True pheasants ringneck type) like the Afghan white- winged (also called the Bianchi pheasant) or the Manchurian ringneck. Those two strains are closer to F1 or only 20 or more years from being removed from the wild. And those two strains are naturally alert and wary of predators.
Macfarlane Pheasant Farm should have both the Manchurian Ringneck and the Afghan Whitewing pheasant.
Look at the article below:http://amarillo.com/stories/2001/12/02/whe_legionsofspo.shtml#.Vhc8CWC7a5Y
Also Google: Bosque Del Apache Pheasants- to see wild pictures of wild Bianchi white winged pheasants that have crossed the the ringneck pheasants along the Middle Rio Grande River.
You already have a few pockets of truly wild pheasants scattered in spots in southern Texas. There are a few wild pheasant south of Bay City Texas. And also they still have a few wild pheasant in Chambers County (but no season).
They have a few wild pheasants frequently seem around the lakes near Cleburne Texas.
Heat is not the problem for Texas pheasants, it is hot in Wichita, Kansas in July, yet wild pheasants are seen all around that area and are expanding southward along the Arkansas river into Oklahoma. Timely rains and nesting cover and predator control will help the pheasants the most.
I say go for it, and keep us posted on your progress. Why should S. Dakota and Kansas have all the wild pheasant fun.