If there pens are full of snow with no dirt showing she could also be looking for dry ground, normally when my Peahens dig holes they are looking for a nesting place or Dirt bath. When it snows here it only last for a day or two.
Also durring the winter my birds were really digging up the whole pen, even the males. I think they were trying to find bugs and grass and since they couldn't find any they were trying to find them all over the pen. And/or it could be that she is searching for a nesting place too.