why there's no "i" after the things possessed? You say "fy nghar i" but "fy nghar du" and the personal pronoun disappears near an adjective? Or it's the matter of multiple things possessed and the conjunction 'a' ?
You could say "fy nghar gwyn i" and it should still be correct but it does feel quite clumsy.
I was always taught 'chwadan' for duck, didn't know 'hwyaden' was another word for it