I don't know, really. I’m not sure there wouldn't be some forms of controls so as not to feed hens that don't lay, or lay unsellable eggs. But anyway I think most would not survive being egg bound or having trouble laying in such conditions.I don’t think so because eggs from caged hens roll out and are gathered automatically.
And battery cages for single hens have been banned in the European Union since 2012. Most battery cages have been replaced by the so-called enriched cage system and by the colony housing system.
In this housing system, the chickens, also called laying hens, live in cages. Around three to a maximum of five laying hens live in a cage and each laying hen has access to 550 cm2 of floor space. This is also called a battery cage.
Food and drink are constantly available, allowing them to do so whenever they feel like it. What does a battery cage look like? The sloping bottom of the cage ensures that the eggs roll automatically onto a conveyor belt. This makes collecting them very easy and the eggs do not have to be picked up from the cage. The hens' manure falls directly through the bottom of the cage.
The bottom is made of mesh, so the manure is virtually unaffected. This is also removed by conveyor belt, just like the eggs. Naturally, this is done with a different method than the one used to collect the eggs. This way the hens and eggs remain clean and the risk of diseases is minimal.
Battery cages banned in the European Union Since 2012, these battery cages have been banned in the European Union, due to very poor animal welfare. What is allowed are enriched cages. These cages are permitted until 2025 and are larger, higher and offer slightly more comfort than the old battery cages. However, this is also subject to criticism, as the living conditions are hardly better than those in the original battery cage. Fortunately, almost no cage eggs are sold in Dutch supermarkets anymore*.
Source: https://www.eicode.nl/blog/kooieieren.html
* This applies only for the whole eggs. In Dutch (eu) supermarkets, imported eggs from single battery cages can still be found in products such as sauces and pastries.
I don't agree with saying that cages are banned because an enriched cage is a cage with 750 cm2 (0.8 sq ft) per hen (600 on the floor) instead of 550 (0.6 sq ft), with a nest, and a dustbath and a possibility to roost. I still call that a cage. As animal rights association point out an A4 sheet is 600 cm2.
French egg industry says in 2023 this is the case for 23% of layers, so that is almost 1 out of 4 ; they are refusing european sanitary advice to put an end to it.