The spring and fall thing is true. Chicks hatched in spring are larger than those hatched in fall, but if you have a rare very expensive breed I would suggest that you hatch even in fall, because the genetics is there. You want to hatch every egg that you can. Once you have made a sustainable...
Congratulations on your project. I hope they are hatching now. If you want to establish your online here are my few tips.
1. always hatch from mature hens, atleast a year old.
2. Try to know how the hens and cocks are related. Avoid breeding true siblings.
3. Weight is inherited from mama...