They are probably hunting on leased property thats managed by a hunting lodge...etc.
A lot of birds are pen raised, and used to human contact (not quite pitch and catch as seen here). They are released a few days prior to a scheduled hunt and quite frequently when dogs point on a cubby - unlike wild birds that are easily flushed - the hunter has to kick them go get them to fly.
Maybe not be exactly whats going on here....but a possible similar situation.