Janet came to the United States in 1839 on the Marion with her son Robert. 
“The ship sailed on July 4, 1839 from Greenock, Scotland. James Picken & family were related to the Giffens (called Aunt & Uncle by the children), and Janet Howie was the grandmother to Andrew's children. Mrs. Picken died during the crossing and was buried at sea. The trip was "stormy" and apparently nearly went down several times. The ship landed Aug 26, 1839. It took the families 35 days to travel from New York to Chicago by rail, and boat. From Chicago, the travelers proceeded by wagon to Rockford, IL. This information comes from a letter written by William Giffen, son of Andrew. William married Margaret Harvey, daughter of William Harvey who came to Argyle in 1841." Joan Mershon
"United States Census, 1850," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:M854-YKD : 12 April 2016), Jennette Picken in household of Robert Howie, Harlem, Winnebago, Illinois, United States; citing family 69, NARA microfilm publication M432 (Washington, D.C.: National Archives and Records Administration, n.d.).