I've not seen a study linking capsaicin to increased viability. I've seen some small studies, sometimes contradicted, indicating increased egg weight identified as extra albumin. So, I'm not rejecting the possibility, but can you link what you've got?
^^^ The only significant, consistent benefit of cayenne powder. Yes, the egg color is nice, but nutritionaly, there is essentially no difference. Other results largely arise from small studies whose findings are contradicted by others of similar size.
One of the largest studies I saw in use...