Thanks for the additional information.I'm John Good Jeffrey's g-g-granddaughter through his son John Henry Jeffrey, whose mother was John Good's second wife Diantha Marie Hilliker Remmel. John's first wife was your ancestor - was it Emma Elizabeth Maddox?
There is a sort of mystery in the 1880 Page Co Census - a boy age 11 listed as grandson of Ann Duncker Jeffrey named John Talbot.Could be the son of one of the older daughters that you found in the 1860 Chester Co, PA Census.
I have Anne Duncker b. 12 April 1824 in Ireland, d. 26 January 1892 in Page Co, IA.She is buried at Maple Hill Cemetery, Amity, Page Co, IA, College Spring Section.The tombstone says "Widow of William Jeffrey." Lisa