Earlier this year, the British Hen Welfare Trust (BHWT) started campaigning and urging consumers to stop buying large and extra-large eggs in favour of medium and mixed-size boxes. Representing some of the producers, the British Free Range Egg Producers Association (BFREPA) also released a statement to support the BHWT plea to reduce the demands for large eggs. 

How does egg size influence hen welfare, and why should we be concerned? Is a large egg really better for that cake recipe? As the nation follows the ups and downs of the GBBO and budding bakers turn to recipe books and the shops, this is my take on the subject as a vet…

Note – all opinions here are my own; if you are concerned about the welfare of your own chickens, please contact your local vet.

Modern layers are highly specialised hybrid hens; with top genetics that will have an influence on the number and size of eggs they produce. The feed they are provided will also have a substantial effect on their productivity; they have highly specific requirements to be met, in order to produce the eggs we all enjoy. A hen will lay an egg on average every 23 hours for the whole length of her laying period. This is normally around 72 weeks (16-18 months).

How do they live?

Bare wire battery cages have been banned in Europe since 2012, but enriched cages are still permitted. Although they are an improvement in terms of space and provisions to the birds compared to the bare cages; these are still considered non-welfare friendly. The hens are under a lot of physiological stress from their egg laying. And added to that there is social stress due to overcrowding and lack of feed and water space. The 5 freedoms are only minimally met. Free-ranging systems (either entirely indoors in barns or truly free-ranging with outdoor access) usually make for happier birds, provided the groups are not overcrowded and there is no competition for the resources.

Why is large egg size thought to compromise welfare?

When it comes to laying, a hen will normally produce eggs of mixed sizes. After all, no two days are the same and as egg production is influenced by many factors such as feeding, genetics and health status, it is no surprise that the average hen’s egg sizes aren’t identical day after day. The egg has two main parts, the white and the yolk; increasing the egg size doesn’t actually make the yolk (the most nutritious part) any bigger. It’s usually the white that makes up for the extra space inside the shell. The hen will need extra nutrients in the diet to produce that. 

Hens will also utilise some of the Calcium from their bones to make the egg shells. If a larger shell is needed then more resources will have to be taken out of her own system. The increased requirements and physiological strain put on the hens to produce larger eggs is more likely to affect their overall health, and make them more susceptible to diseases. One condition that is more likely to occur if a hen consistently lays large or extra large eggs is a prolapse. Without going into too graphic details, it is a part of the hen’s anatomy that is supposed to stay “in”. If it came out due to prolonged strain, is likely to be damaged and injured. Sometimes a prolapse gets traumatised by other birds. Sadly often meaning the one with a prolapse might die if not removed promptly from the group and allowed to recover.

When a bird is experiencing high stress in their productive life (such as being constantly pushed for more, and bigger eggs), they can also suffer from lowered immune response. This would also reflect in poorer ability to fight off infections.

Is the quality compromised by choosing smaller eggs?

Not at all. The quality of an egg is defined by the yolk/white ratio and their other properties such as colour and flavour (among others). People usually remember “a really good egg” because it has a nice flavour and the yolk is a bright yellow/orange, which are normally heavily influenced by what the hens eat. Larger eggs have more white, but the yolk size doesn’t really change much. Many recipes that call for large eggs might do so because the higher proportion of white aids with moisture and protein content. For example, in a meringue that is made by just egg whites, you’d need less eggs overall; for the same finished product. In reality, making up for the slightly larger amount of egg whites coming from larger eggs is easily achieved by using one more of the smaller eggs.

So if the medium and mixed-size boxes are considered to be more welfare friendly (assuming all of the other measures of welfare are also met!), it would help the health of the nation’s hens if we all chose to use egg sizes that better represent the size pattern that normally occurs. A bit of everything, mix-and-match from the small ones, to medium and the occasional double yolker. 

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