What Causes a Chicken to be Egg Bound?

Egg binding is a serious health condition that can affect laying hens. An egg bound chicken has an egg that is stuck in the oviduct and unable to be laid. This stuck egg prevents other eggs from being laid and also blocks the hen’s digestive system. Understanding what causes egg binding can help chicken owners prevent and treat this potentially fatal condition.

What is Egg Binding?

Egg binding also known as oviduct impaction, refers to when an egg gets lodged in the oviduct of a hen and she cannot expel it. The egg usually gets stuck right before the cloaca, but can also become trapped in the shell gland.

When an egg binds the hen’s body goes into distress mode. She will strain to try to lay the egg but the contractions of the reproductive tract muscles are not strong enough to push it out.

The stuck egg stops other eggs from moving down the oviduct at the same time. The hen’s stomach gets bigger because of all the unlaid eggs. The hen can’t go to the bathroom because the cloaca opening to the digestive tract stays closed during egg binding.

What Causes Egg Binding in Chickens?

There are several potential causes of a chicken becoming egg bound:

• Large or Unusual Eggs—Eggs that are too big or don’t have the right shape can easily get stuck in the oviduct.

• Old Age – Older hens tend to have weaker muscle tone that leads to eggs getting trapped.

• Obesity – Excess abdominal fat puts pressure on muscles needed for laying eggs.

• Nutritional Deficiencies – Lack of calcium or other key nutrients makes it hard for muscles to contract properly.

• Dehydration – Without proper hydration, the oviduct can dry out and hinder egg movement.

• Infection or Disease – Illnesses that cause oviduct swelling or muscle weakness.

• Stress – A stressed hen may tighten muscles and be unable to relax enough to lay the egg.

• Cold Weather – Colder temperatures can cause muscle stiffness and spasms in the oviduct.

• Genetics – Some chicken breeds are genetically prone to reproductive issues.

• Egg Laying Disruptions – Such as lack of nesting sites causing a hen to retain an egg.

Symptoms of an Egg Bound Chicken

It is very important to know when a hen is egg bound so that she can get treatment as soon as possible. Most of the time, these are the signs that a chicken is egg bound:

• Straining and abdominal pushing
• Swollen abdomen from backed up eggs
• Lack of egg laying
• Loss of appetite
• Sitting in nest boxes for long periods
• Standing in a hunched posture
• Walking stiffly or like a penguin
• Ruffled, unkempt feathers
• Pale comb and wattles
• Lethargy and weakness
• Tail pumping up and down
• Soft-shelled or shell-less eggs
• Frequent yet unproductive trips to nest box
• Blood or tissue discharge from vent
• Little to no feces

Dangers of Egg Binding in Chickens

When chickens’ eggs get stuck together, it should be seen as an emergency. If a hen stays tied for a long time, she is more likely to:

• Infection – From backed up eggs and feces.

• Internal laying – Egg breaks inside hen leading to infection.

• Shock – The hen’s system goes into distress from the blockages.

• Vent prolapse – The oviduct protrudes outside the vent.

• Egg yolk peritonitis – Infection of reproductive tract.

• Organ damage – From the pressure of backed up eggs.

• Death – Egg binding left untreated is often fatal.

Hens can die from egg binding within 24-48 hours without proper treatment. Quick action is needed to clear the blockage and restore the hen’s normal bodily functions.

Treating an Egg Bound Chicken

If you suspect a hen is egg bound, take the following steps:

• Isolate – Move her to a warm, quiet space away from flock.

• Hydrate – Provide water with electrolytes.

• Check for egg – Lubricate and gently insert finger in vent to feel for egg.

• Supplement calcium – Give crushed calcium supplements.

• Apply heat – Use a warm water bath or heating pad on abdomen.

• Massage abdomen – Gently work the area around the stuck egg.

• Lubricate vent – Use Vaseline to lubricate around vent.

• Increase contractions – Injecting oxytocin can stimulate oviduct muscles.

• Remove egg – As a last resort, collapse and remove shell, see vet.

• Treat infection – Use antibiotics if egg breaks inside or vent damaged.

• Check for prolapse – Monitor vent for swelling or protruding tissue.

• Let hen rest – After egg passes, let her fully recover before rejoining flock.

Preventing Egg Binding

You can lower the risk of egg binding through proper flock management:

• Provide a nutritionally balanced layer feed.

• Offer a free-choice calcium supplement.

• Use proper lighting schedules for pullets.

• Give hens regular outdoor exercise.

• Supply at least 1 nest box per 4 hens.

• Routinely check hens’ health and weight.

• Prevent parasites and infectious illness.

• Select breeds that are not prone to egg binding.

• Discourage obesity by limiting treats.

• Keep coop clean and reduce hen stress.

While egg binding can happen randomly, following best practices for raising chickens can help avoid an unsafe number of incidents in your flock. Act quickly at the first signs of an egg bound chicken to ensure the best outcome.