As BigSweetie has said, there’s a lot going on here. Many of the stones are field clearance, but the cist covers and several recumbent stones (along with the single upright remaining) show that there was a veritable hive of neolithic activity here at one time.
According to a local lady I spoke to, the land belongs to the Abercairney Estate and was at one time used as a burial ground. The estate has been held by the Moray family since the end of the 13th century.