If the white is a white, then either Ice would have to be split white OR a pied hen or another split white hen added eggs to the nest.
Edited by Kev - 8/14/11 at 5:12pm
Split pieds never can produce a white chick. Only whites, split whites or pieds would be able to.
A split white will be able to produce a pied if bred with a pied, dark pied or a split pied.
Due to unknown parentage, too early to assume the one chick with white on wings is a dark pied just yet. It could be split white. For example, Dragon bred with not-split hen would produce half split pied and half split white chicks.
It could be one chick is Ice's and other two are someone else's added to nest after she started sitting. As it seems the chicks hatched very close together, would suspect eggs were added to nest by other peahens close to the first egg as peahens lay one egg every other day... if all eggs were one peahen's, the third egg would be expected to hatch 5 days after the first one.
Lastly but not least, congrats on the Dragon progeny!
edited to add: Is that blue container in second picture full of water? Highly recommend removing all open containers that hold water immediately... peachicks drowning in open containers is a very common problem, due to being able to fly so well while they're still real small.