The horrible conditions battery hens are in

from Do better cages or cage-free environments really improve the lives of hens? - Our World in Data

There are around 8.3 billion egg-laying hens worldwide, around the same number as humans.

Most of these hens live in cages that give them less space than an A4 sheet of paper.

It often has no nest to lay its eggs in; no room to rest; and its movement is almost entirely restricted. It can’t carry out its normal behaviors of foraging, pecking, or dustbathing, so hens will often peck themselves or one another, leading to skin wounds and their feathers being plucked out. In many countries, chickens are ‘de-beaked’ – where their beak is partially removed – to stop this.

Hens are bred to be highly productive. Hens will often lay around 300 eggs per year. That’s very different from the wild ancestor of modern chickens – the red junglefowl – which lays around a dozen per year. And much higher than in 1900, when commercial hens would lay around 80 eggs yearly. The productive period of hens only lasts 12 to 18 months; they’re then killed to make space for younger hens that can produce eggs at a higher rate. Male chicks – of no use to the intensive egg industry – are often culled in macerators shortly after birth.