help with pet duck and goose eggs

I regularly feed the local ducks at the KCKJCC and I have been picking up their eggs and need help on how to incubate them but I don't know if it is the big white goose or the little white duck, they are together ALL the time but their are mallards their also and sometimes Canadian geese but the whites keep to themselves. I don't even know which is female and which is male (of the white ones) I know about the colored mallards. Any and ALL help appreciated PLEASE,.....