I have the box of pollen substitute about 200 feet from my overwintered bees. We have a little bit of natural pollen coming in. This is a better source of protein than having them drag in sawdust and whatever else they may bring in. They are out looking anyhow,so it does no harm. I also have patties inside the hive,but they have not been very interested in those.
There is some natural pollen starting to come in as I can see different colors when they are at the hive entrance. On a plus side, if there are nay ferals out there,I sure would like them to build up too.