MMario and Sorcha,
The lyrics you posted are similar to the version I know. But that one main line is "He once said, as a chucky for his pay, that she was her mother's darlin-O." I'm told that it means he once told her that for a whore/prostitute ["chucky for his pay"}, she was [or fancied herself] pretty hot stuff ["she was her mother's darlin'-O].

The story's kind of between the lines, but it seems they were lovers in their younger years, he knocked her up, promising marriage, and then brushed her off as a whore, and she catches up with him many years later, gets him drunk and has her revenge.

I don't know if your line is just a different version [he really was a jockey?] or if someone mis-transcribed it.

The input from all of you folks is most appreciated. Thanks.

Genie