I would have to say it is possible. It would depend on what the habitat is and what condition it is in. If the drought is hard enough then there will be a reduction of residual cover from the previous year and this and would have an impact on nest success. It also could have an impact on invertebrate production making it more difficult for the chicks to survive.
Talked to a friend in Idaho yesterday and he said there are diffently fewer birds. You would think pheasants being around agriculture would have enough water and the drought would not effect them. Who knows what to think.