How do farmers control whether a chicken lays an eating egg or a reproductive egg and how can they tell which kind is laid?


How do farmers control whether a chicken lays an eating egg or a reproductive egg and how can they tell which kind is laid?

In: Biology

Hens will lay eggs regardless of whether or not they’ve been fertilized. So it’s pretty easy to make sure you’re only getting food eggs – keep the rooster away from the hens.

Chickens will lay eggs no matter what. It’s basically a daily chicken period. Only if they are fertilized by a rooster beforehand will they form baby chicks. If you keep chickens away from roosters, all eggs will be eating eggs.

Edit: I know both fertilized and unfertilized eggs can be eaten. OP said eating eggs and reproductive eggs so I stuck with the same terminology assuming they meant how do farmers know what eggs are able to become chicks and which ones won’t.

> How do farmers control whether a chicken lays an eating egg or a reproductive egg

You remove any roosters from your farm

> how can they tell which kind is laid?

They’re the same thing. If you get a fertilized egg soon enough (eggs are usually collected in the morning or at night every day) then a chick won’t grow and you can eat it like it was never fertilized at all

Chickens lay eggs whether they are fertilized or not, so the easiest way to make commercial eggs is to not allow the males to mix with the females.

But if you need to check an egg you just hold it up to a bright light. You can see enough through the shell to tell if a chick is in there. Commercial operations do this with automated machinery.

All eggs are eating eggs unless you want to hatch more chickens. Hatching eggs require fertilization from a rooster. On commercial farms, hens that lay eating eggs rarely, if ever, are given any ‘private time’ with a rooster. They may bring in a rooster to give them motivation but not allow fertilization. My family raised chickens when I was a kid and we had a rooster. There is a visible difference when you crack open a fertilized eggs because the yolk and the egg white are joined together by threads or tubules. I don’t recall the eggs tasting any different (Summertime eggs were definitely better because the chickens were eating a lot of bugs. The yolk is a deeper yellow.)

Farmers try to control this by not allowing the chickens to mate except in specific circumstances, but this isn’t always a perfect process: preventing chickens from mating can be harder than you might think.

As a second line of defense, they use a technique called candling to detect embryos. This involves holding the egg up to a strong light and looking through it: it’s not *quite* as simple as the process you may have seen in cartoons, but it’s pretty close. It takes some skill to read what’s going on inside the egg, especially at early stages, but you can get a decent read on which eggs are fertilized and which are not.

The eggs will only be fertilized if a rooster has done his job.

You can eat eggs whether they’re fertilized or not. The embryo doesn’t develop unless the egg is incubated either by a hen or a machine.

Eggs can be “candled” to see an embryo.

Just collect them everyday and it won’t matter if they are fertilized or not. Hens have to sit on them and keep them warm for an embryo to develop. If you want to hatch them, you generally put them under a heat lamp for a while.


As an additional note to what others have said, many farmers have a variety of chicken breeds on their farms. Some breeds of chickens instinctually are more attuned towards nurturing eggs by sitting on them. Other chickens have been bred to just pump out eggs and will not sit on their eggs, thus, even if they are fertilized they won’t grow up to become new chickens.

So in a way, another method of controlling reproductive eggs vs eating eggs is through the choice of chicken breed.

I know this from working at an organic farm, but even there, they had incubators to ensure certain eggs successfully led to new chicks being born.

Hens lay fertile eggs within about 3 weeks of being ‘visited’ by a rooster. She then doles out the semen one egg at a time as she lays a clutch. After laying as many as she wants to incubate, she sits on them, keeping them uniformly ~99° F for 21 days.

Fertile eggs are indiscernible from infertile eggs and can only be proven one way or the other by incubating or cracking them open. Only a trained eye can tell the difference, even by cracking and examining. Noticeable development is only present after 5-7 days at incubation temperatures.

Eggs are generally collected within a few hours of being laid, so there’s normally no danger of finding any development, as they aren’t incubated.

TL;DR:  Farmers collect eggs regardless of whether they are fertile or not. Fertilization is absolutely irrelevant, as a normal person couldn’t possibly discern whether the uncracked egg was fertile until day 8 or so of intentional incubation. They look and taste the same either way.

*Somehow deleted part of my response while trying to fix a typo, sorry!

I once cracked sn egg into a frying pan and there was a fleshy lump sitting there sizzling away. I did not have eggs that day

have you never opened an egg and saw a brownish embryo looking thing attached to the yolk? they are all “eating eggs”

Okay…. who’s going to ELI5 the birds and the bees here?

When a mommy chicken and a daddy chicken love each other very much they get together and cluck making more chickens in the process. If kept separate the mommy chicken will keep cranking out duds.