You need to get either game or turkey chick crumbs, which are higher in protein and also have an anti blackhead ingredient, which poultry chick crumbs don't have. These will be ok for your poultry chicks to eat as well.
You also need to ensure that when the chicks hatch they are in a totally chick-proof run, as the pheasant chicks don't understand "hen language" and will tend to wander off and not return when the hen calls to them.
So what you find is that the hen will readily accept the pheasant chicks but they will not initially respond to her and can quite easily just wander off and die of cold.