Australian Breeders MarketMites affect the birth order of baby finches.
An interesting article from PhysOrg.com on a study done on the American house finches.
The article states that when the nest is exposed to mites and other parasites, the mother undergoes hormonal changes to alter the birth order of her off spring, to give the more fragile males a greater chance to survive.
Males did more of the development in the egg, thus protecting them from mites and getting them out of the nest quicker.
Could be an interesting discovery for bird breeders and their struggle for parasite control.