A lash egg looks like a misshapen, rubbery mass roughly the size of a normal egg, often tan, pinkish, or flesh-colored on the outside. It doesn’t resemble a typical egg at all. Instead of a smooth shell, the surface feels waxy or leathery, and the shape is usually lumpy or oblong. If you’ve found something strange in your nesting box and you’re not sure what you’re looking at, the real test is cutting it open.
What You’ll See on the Outside
Lash eggs vary in color from pale yellow to pinkish-tan to dark reddish-brown. Some are small, roughly marble-sized, while others can be as large as or larger than a regular chicken egg. The texture is rubbery and firm, nothing like the smooth, brittle shell of a healthy egg. Many have an irregular, blob-like shape with visible ridges or folds. They sometimes have a foul smell, though not always.
Because they can occasionally have a thin membrane or partial shell coating on the outside, lash eggs are sometimes confused with soft-shelled eggs. The key difference: a soft-shelled egg is still a normal egg with yolk and white inside, just missing the hard shell. A lash egg is a solid mass of hardened, rubbery material all the way through.
What’s Inside a Lash Egg
If you slice one open (wear gloves), you’ll see concentric layers of waxy, cheese-like material that some people describe as looking like thinly sliced deli meat rolled up together. These layers are actually hardened pus, built up in rings as the hen’s immune system repeatedly tried to wall off an infection inside her oviduct. Mixed into those layers, you may find bits of yolk, egg white, shell fragments, egg membrane, blood, or pieces of tissue from the reproductive tract. Not every lash egg contains all of these, but the layered pus structure is the hallmark.
The material itself feels dense and somewhat rubbery when you cut through it. It’s distinctly different from the liquid contents of any normal egg, even a deteriorated one. If you see those unmistakable layers, you’re looking at a lash egg.
Why Hens Produce Lash Eggs
A lash egg isn’t really an egg at all. It’s the byproduct of salpingitis, an infection and inflammation of the oviduct (the tube where eggs are formed). Bacteria enter the oviduct, and the hen’s immune system responds by encasing the infection in layers of pus, which then gets pushed through the reproductive tract and laid like an egg.
The bacteria most commonly involved are E. coli and Enterococcus faecalis, though research has found that co-infections with multiple bacteria tend to cause more severe disease than a single bacterial species alone. The bacteria can enter the oviduct from the cloaca (the shared opening for the reproductive and digestive tracts), which is why nest box cleanliness plays such a large role in prevention.
What It Means for Your Hen
Finding a lash egg is a sign that something has already gone wrong inside your hen’s reproductive system. Some hens pass a single lash egg and continue living normally, but salpingitis is a serious condition. In many cases, the infection is chronic by the time you find the lash egg, meaning it’s been developing for a while. Hens with ongoing salpingitis often show other signs: a decrease or stop in egg production, lethargy, a penguin-like upright posture, or a swollen abdomen. Some hens show no obvious symptoms at all beyond the lash egg itself.
A hen that has passed one lash egg may pass more. The infection can persist or recur, and repeated bouts of salpingitis can permanently damage the oviduct. In severe cases, the infection can spread into the abdomen, causing a condition called egg yolk peritonitis, which is life-threatening. If your hen seems unwell after passing a lash egg, a poultry-experienced veterinarian can evaluate whether antibiotics might help.
Preventing Lash Eggs
Since the underlying cause is bacterial infection of the oviduct, prevention comes down to keeping your hens’ environment clean, particularly where they lay. The University of Maine Cooperative Extension recommends one nest box for every two to four hens, removing soiled bedding and adding fresh shavings each time you collect eggs, and doing a thorough cleaning of nest boxes once a week. If your eggs are frequently dirty when you collect them, that’s a sign your nest box hygiene needs improvement.
Good general biosecurity also matters: limiting contact with wild birds, quarantining new flock members, and keeping the coop dry and well-ventilated. Roll-out nest box systems, where the egg rolls away from the nesting area after being laid, can help reduce contact with contaminated bedding, though those floors still need periodic cleaning. Prevention through good nest design, adequate nest box numbers, and consistent hygiene is the most effective approach, since salpingitis is difficult to treat once it becomes established.