A comprehensive guide to eggs: from ostrich to emu
British hens are estimated to lay ten billion eggs per year. That’s a truly mind-blowing number of eggs. We dive into the history behind our eggy obsession, and take a look at some lesser known varieties.
A comprehensive guide to eggs: from ostrich to emu
British hens are estimated to lay ten billion eggs per year. That’s a truly mind-blowing number of eggs. We dive into the history behind our eggy obsession, and take a look at some lesser known varieties.
Our love of eggs is nothing new – there’s evidence ancient human ancestors ate eggs 300,000 years ago. It’s no surprise they’re so popular when you consider that eggs are designed to hold all the sustenance that a growing chick would need. They’re delicious, nutritious and perfect with almost any meal. However, while we’ve always loved eggs, our love affair with chicken eggs in particular is a surprisingly modern development.
The history of eggs
Although roast chicken is now an iconic part of the British diet, chickens aren’t native to the UK. They were first brought over by the Romans about 2000 years ago. There’s evidence that Romans ate eggs while watching matches and events at the Chester Amphitheatre, as an ancient equivalent of a match day pie. But even after they were introduced to the UK, general consumption of hen’s eggs remained relatively rare. Chickens were farmed, but were also often killed as sacrifices to the gods, and it took time before they came to be popular. Other eggs were popular though – in Scotland sea bird’s eggs would be collected from cliffs, something which is still practised in Iceland.
It’s currently thought that modern day chickens’ ancestor is the junglefowl, and that they were first domesticated in Thailand about 4000 years ago. Since the domestication of junglefowl seems to have happened around the same time as rice and millet farming began, one theory is that the junglefowl were drawn to the piles of grain and so began to become easier for Thai people to capture and domesticate. However, it was only just over 100 years ago – in 1895 – that chicken eggs began to be incubated artificially at a large scale.
Anatomy of an egg
Although when you crack open an egg it looks like there are just two components – the yolk and the white – there is a lot more to it than meets the eye. There are four different parts of the white alone, and each component serves a different purpose. The white has antimicrobial properties, and helps protect the nutrient-rich yolk from infection, and the shell is coated in a wax that helps the shell to be protected from bacteria, but still porous. The egg is absolutely teeming with tricks to help protect the chicken and ward off predators.
In fact, although we take it for granted, the egg’s shell is one of the most incredible things about it. Birds and dinosaurs (their ancestors) are unusual in having hard calcium shells on their eggs. Lizards’ eggs have leathery shells, and fish eggs are soft and squishy. The hard calcium shell keeps the eggs safe, but it is also porous, allowing chicks to breathe as they grow.
Another clever part of the egg is the chalaza. If you’ve ever had a slightly unpleasant white stringy thing in your egg when you cracked it open, that is the chalaza. These strings anchor the yolk in the centre of the egg, and make sure that the embryo doesn’t get flipped upside down and away from the warmth of the hen. Wonderful for chickens, but fairly unpleasant in an omelette.
A guide to different types of egg
Quail eggs
Quail eggs are about a third of the size of chicken eggs, and are delicious served on top of a beef tartare or potato salad. Quail eggs have a creamy off-white speckled shell, and almost twice the iron and riboflavin of hen’s eggs.
Goose eggs
Goose eggs are much bigger than hen’s eggs, and much richer, containing four times as much fat and a large, rich yolk. They are excellent in any recipe where you want a particularly bright yellow colour or rich flavour, like curds and custards.
Duck eggs
Smaller than goose eggs but slightly bigger and richer than hen’s eggs, duck eggs are a particularly popular egg in East and Southeast Asian, where they are often salted. Salted duck egg yolk is then used in pastries, desserts and even as a flavouring for crisps. They’re also a popular filling for mooncakes, which are eaten at the Mid-Autumn Festival.
Emu eggs
Although not quite as big as an ostrich egg, the emu’s egg stands out both for their size and their deep emerald colour. One emu egg is the equivalent of about a dozen chicken eggs, so if you’re cooking the whole thing in one go you’re going to need your biggest frying pan!
Rhea eggs
Rhea eggs are huge, slightly yellow and cook in a similar way to an emu or ostrich egg. It’s actually possible to buy rhea eggs from birds in the UK, as a few farms are now raising rheas commercially for their eggs. One fascinating thing about rheas is that it is the males that incubate the eggs rather than the females, and they can incubate dozens of eggs at a time in a huge nest.
Pheasant egg
Pheasant eggs are a muted, olive green colour and are slightly smaller than chicken eggs. Despite being smaller, they have a thicker egg shell. Pheasant eggs taste very similar to a hen’s egg, and are useful in dishes where a chicken egg might be too rich or too large
Bantam eggs and pullet eggs
Bantam eggs and pullet eggs are two terms for eggs which are smaller than typical chicken eggs. However, they are smaller than average for different reasons. Bantam eggs come from fully grown chickens which are smaller than a usual chicken. Pullet eggs come from hens that are less than one year old. Although they can make up up to 10% of all eggs, they are rarely seen in supermarkets because they don’t fit into typical classifications. They are just as tasty as full-size eggs though, and often have a higher proportion of yolk.
Ostrich eggs
Ostrich eggs are the largest eggs of any living bird (although not the largest eggs of all time – that award goes to the elephant bird!). They are much rounder than your typical hen's egg, and twenty times bigger. The shell is also much thicker, and if you've bought one you're going to need something a bit sturdier than a teaspoon to get it open.
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