Barnacle geese sprouted from barnacles and also they aren't flesh.

BARNACLE GEESE KINDA LOOK LIKE GOOSE BARNACLES & ALSO WE NEVER SEE THEIR EGGS OR CHICKS; THEY MUST NOT LAY EGGS LIKE OTHER BIRDS AND SPROUT FROM THESE BARNACLES; THE DRIFTWOOD ON WHICH BARNACLES GROW FELL FROM THE BARNACLE GOOSE TREE SO ALSO BARNACLE GEESE ARE "NEITHER FLESH NOR BORN OF FLESH" SO WE CAN EAT THEM ON FRIDAYS AND FASTING DAYS