I produced my first pieds last year after 10 years starting with possible het males and breeding to normals. I only kept one pied back but he grew quickly and bred well at less than a year. I've not weighed him lately but at 1 year I'd guess he is in the 700 gram range in spite of really shutting down on feeding once I started breeding him.
I have lost two animals in my collection years apart to an impacted bowel problem that my vet compared to megacolon in cats. Both where POSSIBLE het pieds. I've posted several times if this is seen in pied projects and never gotten any report that it is. Hopefully I'll eventually hatch a keeper female pied or six to grow up and have something more to add to this discussion. Of the 7 pieds I've produced so far (from three different 25% chance het pied girls held back for belly markers that proved) the only female had tied the umbilical around herself and I wasn't able to save her. There was another that died in the egg but I didn't sex it, probably my other girl, lol.