Chai ran through the yard to greet me, her limping seemed heavier. I picked her up and checked if something was stuck under her feet, but I didn’t see anything. She has been slightly limping since her rescue a year ago. I examined her over time and never saw anything obvious, but this time she really seemed in pain, so we went to the vet. They diagnosed her with arthritis which is quite surprising as she is only 2 years old. It could be the result of an old injury at the farm. But the main problem actually was her weight, it put too much stress on her legs. To figure out what was causing this excess weight, they did an ultrasound of her abdomen and they saw a thick layer of fat. As a chicken rescuer, I was expecting a tumor or some egg materials, but not fat! I felt very ashamed that a vet had to tell me that my chicken was obese and that I had to put her on a diet. What a terrible chicken mom!
Unfortunately, it seems that I am not the only one who is overfeeding my girls. Lots of heritage breeds have a tendency to put on fat, especially the ones known to be cold hardy or dual-purpose (bred both for their eggs and meat).
What is the problem with a fat chicken?
There are several health hazards of obesity.
First, a fat hen often has difficulty laying eggs and is more at risk of having a prolapse. She also has a tendency to lay oversized eggs or eggs with multiple yolks which can lead to egg binding, a condition that can be fatal.
Overweight chickens are more prone to heat stroke which is a big issue in warm weather. As they don’t have sweat glands, they rely on respiration to cool down their body. The fat decreases their ability to breathe normally and therefore to cool down.
And finally, the liver of fat hens can suddenly rupture causing internal bleeding and death. This is called fatty liver hemorrhagic syndrome and is the most common noninfectious cause of sudden death in backyard hens (cf. Causes of Mortality in Backyard Chickens in Northern California: 2007–2011).
How do you know if your chicken is too fat?
Many chickens are so fluffy that it’s hard to tell if they are chunky or skinny. Here are 2 ways to find out:
Feel for her keel bone (this is the prominent bone between her breasts). If it is sharp and pointy, she is underweight. If on the other hand, you feel a cleavage, then she is overweight.
Look at the area below the vent. If it protrudes, the hen is too fat.
Other signs of obesity are poor laying, poor shell quality, laying eggs at night, frequent multiple yolks, and prolapse.
I recommend weighing your chickens on a regular basis and keeping a log. In our sanctuary, we are weighing all our hens during their biannual health check. Healthy adult chickens have a stable weight for most of their life.
How to prevent obesity?
You can manage the weight of your birds with diet and exercise.
Feeding your chickens a balanced diet is essential for their good health. Avoid high energy feeds (mostly made of grains) as it provides too much fat relative to protein. Read our related article to see what to feed them. Here, we use good quality commercially prepared layer crumbles. Also limit their treats. Scratch (aka chicken candy), mealworms, kitchen scraps, fruits, and vegetables shouldn’t be fed daily. This is how I have unintentionally fattened up Chai. I gave them left over bread, rice, sweet peas and grapes almost every day. If you want to spoil them, give them greens (lettuce, kale, chards...).
Exercise is important too. Encourage them to roam by offering sufficient space (remember 10 sq ft per chicken is a minimum, more is better). Provide climbing trees, scratching/digging areas... If they need some motivation to move around, provide activities with low energy treats like a cabbage tetherball.
Let’s be cautious and not kill our birds with kindness!
Note that this is an article about layer chickens. Broiler chickens who are bred to be obese (e.g. Cornish Cross) need to be kept on a very strict diet to be able to celebrate their first birthday.