Hi Anne, I have a lot of Fegans in County Down, but I'm not sure from your query what timing you're talking about. Although my GGgrandparents, William and Nancy (Campbell) Fegan, left Down about 1850, my GGgrandfather's siblings remained in County Down.
I have a copy of the Newry Telegraph, dated December 23, 1876, which reports the death of my GGGgrandfather, William Fegan, on the previous day at the age of 106. His father was Henry Fagen. That William was married to Elizabeth McKee, and they had 9 children whose names were: Betty, Molly, Sally, Rosie, James, John, William, Henry, and Edward. Edward, my gggrandfather, was the youngest and born in 1824. I believe that Betty was the oldest and born in 1810.
The other information I have is sparse, but Betty married John Skillan on 27 August 1846, Rosie married William Carson, James married Mary Cunningham on 12 July 1842, William married Margaret McGlaughlin on 10 September 1846, Henry married Margaret Grey on 3 November 1849, and Edward married Nancy Agnes Campbell on 12 April 1849.