Now, a court in the state of North Rhine-Westphalia has found that it's not legal in Germany to kill the chickens. According to German law, no vertebrate can be killed "without a good reason." So the state government has said it will not allow it any more.

But it's not easy to know what to do with male chickens. One farmer has started keeping them, and is selling them for meat after 20 weeks. That means the chickens have a much longer life than the average meat bird, which lives for just 35 days. But that's expensive, and the project only works because some consumers are prepared to pay extra.