Farmer Trotter is the owner and operator of a pig farm. He also keeps bee hives and has been known to herd sheep. According to a magazine article, he also keeps cows and chickens and grows carrots and potatoes. Jem Cole, Terence, and Trevor sometimes work on his farm.
Farmer Trotter is good friends with Farmer McColl and Jem Cole. He presumably worked on several other farms before he got his own farm, including Farmer McColl's and another along the Skarloey Railway. He was part of the team that found Duke and has also driven Trevor on occasion.
Farmer Trotter also has his own field which does not appear to be located near his pig farm. The field is occupied by cows which presumably belong to him.