Checking the RC baptisms for the family. All entries at St Mirin's, Paisley. First date is birth, second date is the baptism:
24/08/1844 & 08/09/1844 - James Hillick, Parents JAMES HILLICK/ROSANNA MATTHEWS
24/06/1849 & 19/08/1849 - John Hillick, Parents JAMES HILLICK/ROSAN MATHENS
24/06/1849 & 19/08/1849 - Susan Hillick, Parents JAMES HILLICK/ROSE ANN MATHENS
30/05/1852 & 01/06/1852 - Mary Hillock, Parents JAMES HILLOCK/ROSE ANN MATHEWS
30/05/1852 & 01/06/1852 - Stewart Hillock, Parents JAMES HILLOCK/ROSE ANN MATHEWS
01/12/1854 & 15/12/1854 - Hugh Hillochs, Parents JAMES HILLOCHS/ROSE ANN MATHESON
Twins obviously ran in the family with the two sets showing