I am revisiting this 1841 census, because I think it is correct for Roderick McKenzie senior.
https://www.freecen.org.uk/search_records/59057843e9379091b14b9486/roderic-mckenzie-1841-stirlingshire-falkirk-1816-?locale=en• The census was taken on 6 June 1841, and Roderick and Margaret married 8 months later in Falkirk on 28 March 1842.
• Roderick is recorded as a wright, which matches his occupation as millwright, carpenter and joiner recorded in other sources.
• Roderick is recorded as born "out of county", and we know he was born in Ross-shire.
• Margaret’s father was a mason journeyman in 1841 Falkirk, and may have also been employed at the same place Roderick was working and residing.
That leads to the question – were the Dougald McKenzie (15) and James McKenzie (15), working as labourers in the same place as Roderick, his younger brothers? Did they also go to Canada at the same time?