I read in another post that some ducks will wait until they have a certain number of eggs before they sit on the eggs to hatch them. If they do not sit on the first however many eggs until that number is reached, will the first eggs still hatch, or will they just rot? I have pekins and magpies. trying to decide if I should buy an incubator, count on the ducks, or put fertile eggs under broody chickens. Thank you for your help.