My experience with natural propagation of ring necked pheasants has been exactly the same as Sean and Midnightman. I have successfully hatched and raised pheasant chicks with bantam hens (hardware cloth was needed to house them as it appears that they don't understand 'chicken talk'). Looking at your set up which is fine for a pair of birds I am even more sure that she will not successfully brood there. I would have a cut off time of a maximum of 2 weeks for holding eggs prior to incubation - at moderate temp and humidity and turned daily.