Now you are really getting into the genetics...if there is a brown undercolour, they are probably e^b, not E or E^R. I strongly doubt that a molt will make a difference. That said, I have a chocolate and a mottled where a molt has made a huge difference. In the mottled, her colouring is is MUCH darker than before the molt. In the case of the chocolate, he has ALWAYS been VERY chocolate in colouring. After his molt he looks black...nothing he has EVER looked like before. I am used to colours looking LIGHTER as a bird gets older....not DARKER.
For those of us striving to create pure black pens, do you all have any suggestions?