There may be another issue here - colour perception. The blue-green boundary is notoriously ambiguous. There have been quite a lot of studies in which people are shown colour charts and asked to name a given sample, and there is a big cross-over between blue and green, i.e. what some people see as and call blue others see as and call green. There's a good intro to the issues in Wikipedia, https://en.wikipedia.org/wiki/Blue–green_distinction_in_languageMy hens have always layed what I consider a pale mint green egg, and I have read all about other chicken owners that get blue eggs. Yet the photos they show look pale green to me.