Understanding Egg Drop Syndrome (EDS)

If your chickens have suddenly stopped laying or you’ve found soft or shell-less eggs in the nesting box, it could be more than just a seasonal change. You might be dealing with a viral condition called Egg Drop Syndrome (EDS). It’s frustrating, but manageable if you know what to look for.

What is Egg Drop Syndrome?

Egg Drop Syndrome is caused by a virus that affects laying hens. It leads to a noticeable drop in egg numbers and a decline in egg quality. You might see:

• A gradual loss of pigmentation in eggshells

• Thin, rough, or shell-less eggs

• Misshapen eggs

• Fewer eggs being laid

Many hens look healthy, which can make it easy to miss the early warning signs.

How does EDS spread?

The virus spreads through direct contact with infected hens and through shared items like nesting boxes, feeders, or water containers. It can also be passed from a hen to her chicks via the egg. The virus lives in the shell gland and is shed onto the egg during laying, as well as into droppings.

Wild birds are common carriers, so the risk is higher in free-ranging flocks. Once it gets into the environment, it can linger in shared spaces and on equipment.

Signs to watch for

The clearest sign is a sudden drop in egg production. This usually follows a pattern:

• Eggs start to lose shell colour

• Shells become thinner or misshapen

• Shell-less eggs appear

Often these shell-less eggs are eaten by the hen or get lost in nesting material, so you may not see them at all.

Some hens show mild signs like:

• Slight respiratory changes

• Loss of appetite

• Low energy

But many show no obvious illness at all.

Managing Egg Drop Syndrome

There is no direct treatment for EDS, but most hens recover and start laying normally within a few weeks. The focus should be on stopping the spread and supporting the bird’s recovery.

• Isolate the hen from the rest of the flock if possible

• Thoroughly clean all equipment, nest boxes, and surfaces she has used

• Support her immune system with good feed and clean water

Even if she looks fine, she’s carrying a virus, and needs time and care to recover.

If it's not EDS What Else Could it Be?

Not all laying problems are caused by EDS. Other reasons include moulting, poor diet, ageing, heat stress, or broodiness. If you're not sure what's going on, a bit of local know-how can help. You’ll find practical advice and troubleshooting tips in our Keeping Chickens online course, designed for lifestyle block owners.