I was helping someone recently who had ancestors that lived briefly at Skallerud, but it was a different family. Most of your data on Anton is correct, with the exception of his place of birth. He was not born in Trogstad parish:
Confirmed at Trøgstad church, Østfold, 12 Oct 1862
#31, Anton Andreasen Skallerud
Born 7 Jan 1848 at Brattefos farm in Trømberg
Father: Andreas Hansen
Mother: Elen Axelsdatter
Kildeinformasjon: Østfold fylke, Trøgstad, Ministerialbok nr. I 8A (1855-1864), Konfirmerte 1862, side 200.
Permanent sidelenke:
http://www.arkivverket.no/URN:kb_read?idx_kildeid=451&id...Trømberg parish is not too far from Trøgstad. For periods of time, Trømberg was a sub-parish of Eidsberg.
Here is Anton's birth record:
#6
Born 7 Jan 1848
Place of birth: Søndre Berg farm in Trømberg sub-parish
Father: Andreas Hansen
Mother: Elen Axelsdatter
Kildeinformasjon: Østfold fylke, Eidsberg, Ministerialbok nr. I 8 (1832-1848), Fødte og døpte 1848, side 142.
Permanent sidelenke:
http://www.arkivverket.no/URN:kb_read?idx_kildeid=2&idx_...As you can see, his birth record says he was born at Søndre Berg, and his confirmation says he was born at Brattefos. I would go with Søndre Berg as this was recorded at his birth. Brattefos was recorded 15 years later when he was confirmed. At any rate, he was born in "Trømberg i Eidsberg" - not "Trøgstad". He moved to Trøgstad at a later date, but before he was 15.