Spots on chicken eggshells are usually caused by irregular pigment deposits during the final stages of egg formation. The shell itself is made primarily of calcium carbonate and is typically white in its natural state. The colour and any additional markings come from pigments secreted in the hen’s oviduct as the egg passes through. One of the most common pigments, protoporphyrin, produces brown hues and is also responsible for the speckles seen on some eggs.
When pigment is deposited unevenly, it results in dark spots, flecks, or streaks—usually brown on a lighter background. The intensity and pattern can vary not only between breeds but also from one egg to the next, even when laid by the same hen. This is often due to minor changes in the hen’s body, stress, nutrition, or age. A hen that lays speckled eggs one week might lay smooth, even-coloured ones the next.
Some chicken breeds are more likely to lay speckled eggs than others. For example, Welsummers, Marans, and some types of Barnevelders are known for their richly coloured and sometimes speckled eggs. These variations are purely cosmetic and do not affect the taste, freshness, or nutritional value of the egg.
Spots may also serve a purpose. In wild birds, speckles can help camouflage eggs in nests, protecting them from predators. While domesticated hens no longer need such adaptations, the tendency to lay speckled eggs may still be influenced by these ancestral traits.
Importantly, speckled chicken eggs are safe to eat. The spots are on the outside of the shell and are part of the natural pigmentation process, not a sign of disease or contamination. In fact, many people find speckled eggs more appealing and enjoy the uniqueness of each one.
In short, speckled chicken eggs are a beautiful example of nature’s variety. Whether from genetics or environment, each speckled shell tells a story, making breakfast just a little more interesting.