What factors influence the color of egg yolks?

The color of egg yolks is primarily influenced by the pigments present in the hen's diet, most notably carotenoids. These pigments are found in various foods that hens consume, such as corn, alfalfa, and marigold petals. When hens eat a diet rich in these carotenoids, the pigments are deposited in the yolk, resulting in a more vibrant yellow or orange color.

This means the dietary choices made for the hens play a significant role in determining yolk color, which can vary based on the specific ingredients included in their feed. For instance, a diet high in yellow corn or orange-hued marigold petals will produce darker yolks compared to a diet low in these pigments.

While factors like the hen's breed may influence overall health and egg production, they do not significantly affect yolk color directly. Similarly, temperature during incubation is not a factor that impacts yolk color but rather influences chick development. Total feeding time does not correlate to yolk color either; it does not change the nutritional quality of the hen's diet or the presence of pigments in the feed. Thus, the correct answer highlights the crucial role of diet in determining yolk pigmentation in eggs.