I'm having the same problem. I have 6 non-spoiled, non-hatchable eggs: 3 normal, 1 orange, 1 blue, 1 obsidian. Got them from my coop in the last day. No matter what I cook, the eggs aren't being used in the recipe. But the other food I have in stock will. I've split the eggs between the fridge and my personal inventory in the hopes at least one of them somewhere will be used, but nothing. I have no mods and don't have the Simple Living trait on the lot. I have all expansions except werewolf, high school and laundry.
Has anyone else experienced this? I was so looking forward to eating the obsidian egg 🙂