Not sure if you have these births or not.
All are the children of Adam Shepherd and Betsy Herd and all born Dunfermline. (these are the actual IGI extracts and not the entries submitted by individual members, you might want to check them and see if there are any more)
John Shepherd born 29 OCT 1823
George Shepherd born 17 AUG 1835
William Herd Shepherd born 06 MAY 1826
Alexander Shepherd born 22 JUL 1830
George shows up on 1851 Census in Dunfermline listed as a lodger with brothers Alex & William.
In the home of “Watter” & Elizabeth Drysdale.
IGI shows a marriage for Walter Dryburgh and Elizabeth Shepherd 02 Jan 1849 Dunfermline, Fife, Scotland.
Might be an older child or sister of Adam?
Cheers
Heather