(Bloomberg) -- Cal-Maine Foods Inc., the top US egg producer, is noticing a major trend in the market: consumers are shifting to fancier varieties that they consider to be more sustainable.  Think cage free, pasture raised and organic. The specialty varieties are now becoming the default when it comes to egg buying for many Americans. While that’s boosting sales for Cal-Maine in those segments, conventional eggs are still by far the bigger part of the business for the company and the consumer pivot has be ...