The Great Hatching Egg Swindle

Views 2 Likes Comments Comment
Like if this guide is helpful
Paste a YouTube Video URL
Link to an eBay page Remove
Add up to 3 more photos
Add a caption
Link to an eBay page

The vast majority of eBay sellers (and buyers) are completely honest but there are a small number who will try to extort something and live eggs are ripe for this sort of abuse. Over the last few years I’ve built and designed a number of incubators and dealt with a number of sellers who have all been brilliant; but being active in the community I’ve heard of other buyers and sellers who are not so honest. This guide will look at the pros and cons of the great fertile egg swindle. Problems during and after incubation are many and varied and this guide will not look at those - right now, I want to address the issues of shipping, handling, false claims and what to watch out for.

Nature is a wonderful thing and eggs are one of evolution’s finest designs - they’ve been around a lot longer than humans - dinosaurs were all egg layers - and they were being used long before mammals came on the scene changing little over the epochs.

Here’s some science - but you can skip it if you want. Inside a fertile egg is a tiny embryo - the first few living cells that will, with the right conditions, eventually become a living, breathing bird, reptile or even a fish. While this guide is primarily concerned with bird’s eggs, much of will apply to eggs in general in a state of natural metabolic torpor (that’s a rest state). You might compare this with the diapause employed by simpler (aquatic) organisms such as brine shrimps and triops where the eggs stay in a form of stasis for months or even many years before hatching. Evolution is slow - painfully slow and while the natural technology behind birds eggs has taken millions of years, nature didn’t plan for (drum roll please, maestro ) the postal system.

So if you’re a buyer you’ll have doubtless seen (or soon will) the “get out of jail free” card along the lines of “Don’t leave me feedback on fertility” or “I’m not responsible for the postal system” and if you’re a seller you probably have one of those notes on your listings.

Seems fair enough - you pack the eggs, believe them to be fertile and you have no control from there on.

This is where nature plays a blinder.

It’s not widely known today, but in the 19th century, when artificial incubation was first being tried out eggs were shipped not just around a Great Britain; but across the ocean in ships - a voyage of about 30 days without benefit of fancy packing and many survived to hatch on arrival. This is remarkable - extending the theoretical viability of a hen’s egg to around a calendar month.

What isn’t recorded is the results of those chicks after hatch - and it’s likely that many subsequently died or had other problems. The fact that any hatched at all after a sea voyage calls into question much of the anecdotal evidence aimed at the various postal systems and puts some (not all) of the blame firmly on the sellers who are probably selling duds in the first place.

As a buyer, you have a responsibility to ensure that you incubate correctly too; you can’t expect to order a batch of eggs and then complain to the seller when they don’t hatch because you used a home-made or cheap incubator; or perhaps did something else wrong - and there’s a lot that can go wrong for those new to the hobby.

Hygiene is vital. Eggs are porous (they have to be so the developing embryo can breath) and that means that many bacteria can easily pass through and this problem is particularly troublesome when eggs are washed either at the wrong temperature or even at all!

Sellers: if your eggs are coming out dirty- you’re doing something wrong! Don’t clean them and figure out what’s going wrong.

Buyers: always refuse dirty eggs. A few little marks are OK but if eggs are covered in dirt or faecal matter you can be sure that the seller isn’t taking care of their breeders.

It’s possible (and generally impossible to detect) that a seller has washed their eggs before dispatch and, done correctly, this can be a good thing. Egg wash can remove any trace of external bacilli and leave a coating to keep them at bay. However, there is a fair amour of science and care required here since if the water bath is too cool (cooler than the egg) the egg will imperceptibly shrink and in doing so the bacteria get sucked inside where they will start to multiply the moment they get warm and an incubator is a perfect environment for them - warm and damp.

Clean, unwashed eggs are better. Mother nature knows best and she’s been doing it a lot longer than we have.

The eggs you buy at the supermarket are washed by machines - at the correct temperature - but they aren’t going to get incubated either. Like the embryos, the bacteria develop very slowly (if at all) when they are kept at low temperatures - say below about 18c; so even if any are present (which is unlikely) they’re simply not going to multiply and cause harm despite what a certain UK MP once remarked…

Cool is the key - cold is not. 




So your eggs have arrived - the first thing you’re going to do is remove them carefully from the packing. This is where most sellers claim that problems arise: your eggs, your problem.

This is simply not true - correctly packed eggs can survive a considerable amount of jostling and climate changes - good packaging can prevent that entirely; but not all packing is good packing even the stuff that looks good harbour hidden dangers. In the interest of disclosure I should mention that I have friend who has developed the best egg shipping system I have ever seen so rather than run down everyone else’s system, I’m going to tell buyers how to spot duds.

Your eggs are here. The first thing you should do is check to make sure the seller has mounted the eggs fat end up and marked that clearly on the OUTSIDE of the box. Leave them in there.

This isn’t a joke.

Although you can’t see it yet (more of that in a moment) part of the egg’s inner membrane is split into what will eventually develop into an air pocket. This takes place over the 21 or so days from being laid to the hatch. This seemingly innocuous can help you figure out how fresh the eggs are and how they have been handled.

You need to put the package away now and leave those eggs fat end up - just like the seller has written on the outside of the box - and let them settle.

If the seller hasn’t written on the box (tut tut) you can carefully, with your clean hands or surgical gloves, remove and examine each egg for damage with your candling lamp, putting them back in a box fat end up and leaving them for 24 hours at room temperature.

If the eggs are in the packs at all angles, this is a sign that the seller isn’t taking care with their packing. Candling in this case will probably spot problems listed below. Once you’re statisfied the eggs are OK and discarded any obvious duds follow the instructions above placing them fat end up.


You do have a candling lamp, right?

Sellers and buyers should have candling lamps - the brighter the better and both should use (respectively) before dispatch and upon arrival.

If you don’t have a candling lamp, you’re really not prepared to incubate eggs and while that seems harsh this is a basic part of the kit that you can’t be without. A small LED torch (I find the genuine CREE to be the best) can be had for a few pounds up to perhaps £20UK and is an invaluable diagnostic tool.

Initial candling won’t tell you if an egg is fertile - at this stage the only way to do that is to open it up and that will kill the contents unless you have a laboratory and some pretty clever stuff. There is a way to check the averages which I’ve detailed at the end of this piece.

Candling can identify cracks, misplaced or moving air cells (saddles), old eggs, thin shells (windows): even snapped chalazae and damaged yolks.

Some of these problems are less serious than others. Cracks are sometimes caused when the chicken lays the egg but more often by poor handing somewhere in the dispatch chain. As a rule, all cracked eggs should be discarded - even if they are otherwise OK. Leaking eggs should always, without exception, be thrown away.

Internal cracks and the little taps that show up on the candle can, with care, be covered with a little nail varnish. Sounds crazy, but if these are precious eggs and you’re willing to take the risk, this technique is known to work; better if you have a separate incubator in case one or more turn out to be “rotters” and kill the otherwise viable embryos. I must stress that this is highly inadvisable and should not be attempted unless no other choice is available. (A related technique is used in Asia to colour white Silkie chickens by injecting the egg with a special dye.)


Old eggs will have a partially developed air cell. Air cell development is very slow until the egg is place into a warm environment so if there’s any sign of development, you can be sure those eggs are not as fresh as they should be. There’s not need to discard them at this stage (remember the eggs going from England to America in the 19th century?) but they should be treat with caution - and a sign the seller isn’t paying enough attention to their stock.

This, incidentally, is how you check the age of shop-bought eggs - by placing those in water before us, older eggs will start to rise and stand to attention - while staying on the bottom. Very fresh eggs lie down and can roll around; but as the air cell gets larger they tend to sit up and eventually stand up straight. Eggs in the last days of incubation also float - this is normal - but that’s not a technique I’m going to cover here.

A very old egg or a rotter (that is, an egg that’s actually gone off due to bacterial ingress) will float. Eggs like this are not suitable for anything and should be discarded carefully in case they explode - and trust me, that’s not a smell you can rid yourself of in a hurry.

Broken chalazae (the proteinous “rubber bands” that suspend the yolk) can be broken in transport - and this is one area where packing is key. If one of these comes away from the inner part of the shell the yolk will float and the embryo will be destroyed. Similarly, when examining the eggs, a good lamp (and an experienced eye) can see smashed yolks - although that is thankfully very rare. In either case these eggs should be either discarded or marked as suspect before being set.

Windows is a non-scientific term for the varying thickness of the hard outer shell which can be seen when candling for the first time. Windows are not, in and of themselves, a bad thing. Most eggs will have some - and experience (and internet searches) will show you which ones took suspect. Eggs with a lot of visible windows may indicate very young or older layers or malnutrition or they may even be just something that particular bird does. What you’re looking for is a nice balance - if the shell is too thick, which does happen if the hen gets too much calcium, the chick may be unable to pip or free itself resulting in death. Note: this isn’t the only reason chicks die at hatch, just one of them; and a rarer one at that.


Detached air cells are common but nothing to worry about unduly - this is the reason eggs should be stored and shipped fat-end up because the cell is less likely to move in this configuration. Eggs stored or shipped on their backs or thin end up are highly likely to have displaced air cells - but in many cases, storing fat-end up for 24 hours will allow the cell to right itself while the inner temperature stabilises to its environment - which is, of course, why we do it. Although the eggs are degrading (and hatch viability) begins to drop from the moment the eggs are laid, you can take some comfort in the knowledge that nature allows the torpor to last at least 7-10 days (sometimes longer) without noticeable losses - which allows mother hens to collect a clutch of eggs over several days and incubate them all as a batch.

So, the question of fertility.

You’ve bought something that is described as a fertile egg - but without opening the egg to look there’s no way you can tell which are fertile and which are not. Once you “set” them - you’ll know in a week (first incubation candle) but the seller could equally claim that your incubator or technique was deficient and they might be right.

If you can afford it (and not everyone can) you should buy more eggs than you intend to set - and then, about twice as many and you hope to hatch… and of those around half will be boys so you need to know what you’re going to do with those.

Using strict averages, 50% of hatched eggs are cock birds but not all eggs will be fertile and not all fertile eggs will hatch.

The reason I suggest buying extra (or a least, a half a dozen spare) is that you’re going to throw them away. In an ideal world, you can do this “litmus test” on the duds that you’ve spotted which have cracked during shipping but with a good packing strategy all the eggs are going to be OK.

Randomly select some of the (cough) volunteers (cough) and, one by one and with extreme care, open and remove the contents onto a plate or something similar that you can clean. Ideally, do this with some shop bought eggs before you start this process so you have something for comparison.

It’s colloquially known as a bullseye - because it looks a little like an eye. This little clump of cells is, OK was, the developing embryo; which started dividing long before the mother hen wrapped it in a hard shell and only stopped some hours after she laid it and is now in suspended animation. If you google for "Hens Yolk Bullseye" you should find some examples.

If you find one of these you know you had a fertile egg and it’s likely the seller isn’t one of these people who ship eggs in the full knowledge the hens have never had sight of a cockerel.

At your discretion you can then set the eggs you have left (remember, not all of them will hatch as a rule - even in nature 80% is a good result) or continue to check.

One infertile egg is meaningless; a dud like this are common in nature which is why you should check as many as is practical to establish if you’re being supplied with deliberate duds or good quality eggs.

If you’re careful when examining the eggs for fertility, the remains can cooked and eaten but that’s something even I find a little icky.

May your hatches and your purchases be free from rotters…
Have something to share, create your own guide... Write a guide
Explore more guides