I think those crayfish bought by the sack are red swamp crayfish. They get big and if reproducing and recruiting they could be invasive causing problems of muddy water in your pond. Have a good plan of eliminating them if they cause lots of unwanted problems. Ohio native crayfish that are smaller are less likely to cause pond problems.

aka Pond Doctor & Dr. Perca Read Pond Boss Magazine -
America's Journal of Pond Management