Karen, I have a Farquhar McRae whose mother died in 1849 and he was with his maternal grandmother in the 1851 census along with his sister in Middlesex. Family legend has that the father left and went to Detroit without his children. Parents were Mary Dobie and Farquhar McRae. Is your Ferris family connected to Glencoe, Ekfrid Township, Middlesex county?
He and his sister do not show up in the 1861 census and I wondered where they went.