have had your stomach fed?

It means have you had your stomach filled.
"had" is the past tense and past participle of Have.
"be had" informally means to be made to fill full.eg:-I'm afraid you've been had your stomach fed up!
The whole sentence be:-
Have (you had) had your stomach fed?
The past tense and past participle of feed is fed(verb)
To give food to a person;
feed sth to sb; eg:-
Feed the food to the stomach.Or
have had your stomach fed.

中文即係 你填飽你個肚未？