From your description, this sounds like winter burn. If you had several storms with cold temperatures and extremely high winds as we did here in New England, this is most likely the cause. Leaves and branches on the windward side would be brown and curled, while those on the lee side would remain healthy and green. It may be that in your clearing out, pruning and relocating you removed or thinned some plants that acted as windbreaks. In most winters this probably won't matter, but cold coupled with high winds freeze dries the leaves.

Chances are you have rhododendron maximimum. Big, tough, late blooming growers native to PA. They are not dying. Wait a while, then prune back the dead branches to whorls of leaves or buds. It may take some time, but they will recover.

We had a lot of snow this past winter. You might be seeing damage caused by the snow load. If so you will probably have to cut back to where the damage is.

As maingrower said, give them a chance and then cut back the parts that are dead.

Along with the snow, we had devastating deer damage. It is very distinct. The leaves are almost gone with jagged edges on what's left.

Here is a link that might be useful: How to care for rhododendrons