My birds don't go outside at all. So it must be in my feed.The eggs are yellow because they are eating more feed than forage. It's dark, leafy greens like spinach, kale, chard, cabbage, and most common and abundant green - GRASS, that give eggs that bright orange coloring. Instead of letting them fill up on feed first thing in the morning, try tossing some feed out in the area just outside their run. This will encourage them to start working for their food.