Thanks for your question about transplanting sword ferns. Our native sword fern (Polystichum minimum) is a very tough plant, and even large specimens can be successfully transplanted. That said, it is always best to leave native plants in their habitat, unless you are salvaging them from a construction operation or other disturbance. Sword ferns are commonly available at many nurseries - you should have no trouble finding them.
If you do want to transplant some, the best time is after the fall rains start, but before the new fronds start to grow in the spring. You can cut off the old fronds if it is a very large plant, to make it more manageable. Dig out a good root ball - they are not deep rooters, so wide is more important than deep - and plant them in moist soil in their new location. Water them in well, mulch the area (preferably with leaves or arborist wood chips, not bark!) and they should settle in just fine. 

Oh, no! Not bark?! That's exactly what I had planned bark rock, as a matter of fact. Why must I NOT! do that? (Thanks for the warning.)

Well, you CAN use bark, but it does almost nothing to improve the soil. If the ferns are already going to be growing in an inhospitable location, they would appreciate some organic matter in the soil. If you really want bark, how about putting a layer of compost or decayed leaves underneath it, then put the bark on top so it looks the way you want?

Thanks for the clarification. I can do just as you say; I will.