I'm with nchls on this one. He's been working to selectively breed smallest of his flock. his comment was about hatching time with eggs and that his tiny birds are taking slightly longer in the egg than the larger birds he started with.
Also froggie about your comments about hatching eggs from pullets. From what I have read and experienced hatching there are few problems hatching from young birds if you know any kinks have been worked out of their egg production. I.E NOT selecting eggs from birds who produce more double yolks, porous shells, leather eggs or birds that have a great disparity in the size of eggs produced. Once the laying of a particular bird had stabilized there should be few issues as long as the bird is healthy with proper nutrition. This requires close flock managment, and knowing which birds laid what, but over all health will not be compromised in the chicks who hatch from pullets, although you may see a reduced hatch rate.
Also comparing mammal reproduction to egg layers is worse than comparing apples to oranges, birds have a completely different way of allocating resources to their young.
Nchls is a great source of info for anyone seeking to hatch, raise or breed serama !!!