Early family groupings.

From the entries in the Kirkmabreck parish registers from 1703 onwards, we can see that there were several Heuchan men who were fathering children in the parish during the early 18th Century...Patrick, William, John and Alexander.
The 1671 will of Thomas Heuchan of Blairs, Kirkmabreck Parish, mentions sons Patrick, Walter and John, so it is most likley that these Heuchan baptisms were grandchildren or great-grandchildren of this Thomas Heuchan.

About 17km away, in Girthon parish, there was another family of Heuchans being born around the same time period. The parents were Thomas Heuchan and his wife Elizabeth McSkimmin, who had married on April 12, 1716, at Girthon. Children located for this couple are:
Patrick son of Thomas Huchan and Elizbeth McSkimmin was baptised,14 July, 1717, Girthon.
Jane daughter to Thomas Heuchan and Elizabeth McSkimmin in Clachan baptised February 7, 1720, Girthon.
Alexander son to Thomas Heuchan and Elizabeth Skimmin in Clachan baptised June 16, 1723, Girthon
Thomas son to Thomas Huchan and Elizabeth McSkimmin in Drumwal baptised March 23, 1729.

Why I think this family are related closely to the Kirkmabreck Hughans is the fact that eight years before the marriage in Girthon parish of Thomas Heuchan to Elizabeth McSkimmin, there was a marriage between Alexander Huchan, of Kirkmabreck, to Margaret Diddiston, also at Girthon, on 16/03/1708.
This is the couple who lived at Burns, Kirkmabreck, raised a large family and are both buried in the old Kirkmabreck Kirkyard...

" Burying place of Alex Hughan late in Burns died 28.1.1733 aged 63, wife Margaret Dunniston died April 2, 1757, aged 75.Children Samuel, Peter, Alex, Helen, Agnes and Jean. Erected by Andrew Heuchan in Creetown died 20/01/1809 aged 83. Wife Elizabeth Moat died April 26, 1789, aged 51." This Andrew was also the son of Alexander and Margaret, as we have his baptism record from 1725-Alexander Heuchan in Burns a son Andrew.