I have a Bantie, don't know which one, that is laying bad eggs. The eggs are usually the smallest eggs so maybe they are from my youngest? Anyway, when I crack open the egg, part of the yolk is the normal color, texture, appearance. Then it seems like it's surrounded by a darker yellow and greasey looking substance. I take the eggs daily and they go right in the frig so I guess they can't be 'spoiled'. None of the banties appear sick. One sneezes but has no other signs of illness. Any ideas?