Any guesses on these mixed ducks

[mamato3]

the front ones are pekin. but im after the 2 spotted girls. He bought them this way so breeds unknown he thinks there is some mallard in them. If there is mallards will they fly away? To me i see runner in them. When will they lay? Im new to ducks right know i got 4 3 month old sovies so still learning about breeds
http://joplin.craigslist.org/grd/1887055836.html