I wonder if your local university extension office might have a scientist who might want to look at that. Everybody's studying nutrition like crazy lately. The oranger color MIGHT be related to Omega3 fatty acids, if your hen has been eating certain things higher in Omega3's and concentrating them into her eggs. Mostly, nutritionists are searching out sources of Omega3's vs. Omega6's in foods.
Or, she may be getting red gummybears or other artificially colored snacks from a friendly child? Or iodine-rich seafood?