Bobby Darin's song:
Johnny:
If I had my druthers
I'd druther have my druthers
Then anything else I know.
I believe it is a sloppy spoken "If I had my rathers".
(If I had my choices...)
I've checked several dictionaries, all of which derive it ultimately from
would rather, except for the Online Etymological Dictionary which traces it back only as far as
I'd rather.
In its etymology for
druthers the Oxford English Dictionary gives some former variant forms:
'druther(s) and
'ruther(s)--note the apostrophe on the latter, standing for the elided
d.
I'm in my mid-fifties and use
druthers occasionally. It wasn't part of my mother dialect, however: I adopted it later.