Chickens have one hole – of which they poop, pee, and lay eggs out of. This hole is called the cloaca or vent, and it’s found at a chicken’s rear under the base of their tail.
In this article, I’m going to take you through a crash course in chicken anatomy. I’ll clear up some of the rumors, myths, and misconceptions of how chickens pee, poop, lay eggs, and more!
Do Chickens Have One or Two Holes?
Chickens – like other birds – have one hole or exit when talking about how their urinary, digestive, and reproductive tracts work.
This is very different from our anatomy and that of other mammals and most animals. To state the obvious, we pee and poop from different holes so we have two ‘holes’.
So, it’s not that stupid of a question asking how many holes chickens have – but now you know!
Do Chickens Pee and Poop From the Same Hole?
Chickens do pee and poop from the same hole, yes.
This is because chickens do not have a urinary bladder or an external urethral opening like we do.
I bet you’re wondering how they pee, right?
First of all, there is a myth that I see or hear from time to time that chickens pee through their skin.
This is absolutely not true.
I can see why people would say this. Chickens do not visibly pee like we do as they do not have a bladder to collect urine, and do not pass urine as a fluid.
The truth is that chickens and other birds remove the nitrogen in their bodies through their kidneys as part of protein metabolism.
They then convert that nitrogen into uric acid, which in turn is passed through their cloaca mixed with their poop.
Uric acid crystals are not water-soluble. If you look at some chicken poop (gross, I know, but interesting) you’ll see something that looks like white crystals.
This is the uric acid, or ‘pee’.
Related – More on how chickens pee!
What Hole Does Egg Come Out of Chicken?
As chickens only have one hole for all of their bodily functions (ignoring their beaks of course), it’ll come as no surprise that eggs come out of the same hole as their poop and pee.
Realizing this often puts some people off the thought of eating eggs, but it really shouldn’t.
First of all, chickens aren’t able to poop and lay an egg at the same time. If they were, it would cause quite a mess.
The reason why this is not possible is that when a chicken is in the process of laying an egg, the tissues of its uterus extend to create a barrier from its digestive system.
This is their natural defense against pooping and laying an egg at the same time. But it doesn’t mean you’ll never find some poop on an egg in your chicken’s nest boxes.
If you do find poop on an egg, it’s likely because a chicken has pooped on the egg after it was laid.
Related – How to properly wash fresh eggs.
How Do Chickens Mate?
Both roosters and hens have the same one hole, a cloaca. To mate, a rooster mounts a hen and lowers his cloaca to touch the hens.
The hen also inverts her vent to make better contact, and then the rooster will transfer his semen into the hen.
This might help explain something else that often causes confusion. Without having a rooster in the flock actively mating with hens, eggs are not fertile.
If you buy eggs from a supermarket there is almost no chance that they will be fertilized. Most eggs are laid in a controlled egg farm environment, and there are no roosters present.
It’s typically only when you buy eggs from farmer’s markets, backyard settings, homesteads, and other places where there may be a rooster that you have a chance of finding a fertilized egg.
Even then, you’ll never know unless the egg is incubated so the embryo can develop. There is nothing wrong with eating fertilized eggs, they taste no different and you’ll not know!
Related – Can chicks hatch from supermarket eggs?
Hopefully, the anatomy of a chicken should be a lot clearer now. Chickens have one hole through which they poop, pee, and lay eggs – but it’s not as dirty or as gross as it sounds!
In fact, it’s really interesting how chickens produce eggs and some of the other workings of their digestive system.
Image credits – Photo by Sarah Halliday on Unsplash
Do birds pee? – MercuryNews.com