They are carrying an over capacity in my mind. It is not uncommon to see a good size field with 1000 pheasants in it and yes they are all wild. It is fairly localized to a relatively small region, maybe 2 or 3 counties. the Western part of the state had a couple of Nasty blizzards that hit the area early in the Winter that iced and snowed everything in. The winter just never let up and with the brutally cold Jan and Feb it just made the problem worse. This region is normally very arid and does not get anywhere near the snowfall as the eastern 2/3rd's of the state. As I stated previously they lack the wetlands which are crucial habitat in the more snowy central and eastern portions of Nodak and when you get a winter such as this the CRP becomes socked in and hard crusted, pushing the birds to the only available winter cover left... Shelter belts in and around the farmsteads.
With that may birds congregated in such a small area the competition for food becomes intense. You literally have the "only the strong shall survive" scenario and a massive die off as a result. This winter was definitely been an exception to the rule. The other problem as I see it is the CRP has started to come out and will continue so for the next couple of years. The reason Phez have flourished in this area in the first place has been the abundance of quality CRP combined with normally mild winters and drier spring nesting conditions than further east.
These next couple years you are going to be seeing a big drop off indeed.