|Marriage||He married Janet Dick at Scotland.|
Familysearch has a database: Scotland Marriages, 1561-1910, FHL microfilm 1,041, 471. This is a transcription which shows the marriage between Robert Hay and Janet Dick on June 1st, 1818, at Symington, Ayr, Scotland. The evidence that they are the parents of William and Robert Hay and their siblings isn't conclusive. If indeed they were the parents of William and Robert and their listed siblings then there were earlier children who remained in Scotland and who are unknown to us.