Something else: I have read somewhere sometime (do not ask me when or where, I do not remember) that wild ringnecks in Ceylan use to double hatch every breeding season while in India (same longitude but different latitude) they only have a clutch per year. Probably this is related to refractorinees caused by the long days: in Ceylan light time is shorter than in India during summer. Something on this subject here:
http://jbr.sagepub.com/cgi/content/abstract/7/1/13
And more: somebody in this forum wrote several days ago that he has a pair which is early breader and use to have two clutches every year.
I do not have enough background to conclude anything, but some questions:
1/ Is there an hereditary pattern os sensitivity to photoperiod?
2/ I guess the answer will be yes .... so: how is it inherited for males and females? Or it is just for females since reproduction needs much more energy from females than from males? Every year I see males displaying sometimes for months before the girl is ready.
In fact it is always the lady who says when, where, who, .... lol!!!If it is just a female feature and it goes from mother to daughter I guess there must be strains of precocious naturally double hatching birds. This could help birds adapting to new environemental conditions.
3/ Sometimes it has been pointed here than temperature and humidity could influence breeding, mainly from australian breeders, who face more extreme whether conditions, but .... is there any real study/research made on this subject?
4/Are there mutants having lost this sensitivity to photoperiod and being able to breed all year around? Photosensitivity helps animals to adapt to new environement and to success in breeding, but when they are kept in captivity with free acces to food and water (like hens) we should expect to see this kind of mutants.
Waiting for answers, comments, .... brain stormign, lol.