~In fact, your link is out of date~ (edit - see below). Here's the RSPCA specification from August 2017: https://science.rspca.org.uk/documents/1494935/9042554

~In fact, your link is out of date~ (edit - see below). Here's the RSPCA specification from August 2017: https://science.rspca.org.uk/documents/1494935/9042554/RSPCA+welfare+standards+for+laying+hens+2017+%28PDF+4.46MB%29.pdf/fd2c382d-1a4a-29ee-781f-158c34ca6082?t=1557668428002 https://science.rspca.org.uk/documents/1494935/9042554/RSPCA... Point E 5.3 specifies no more than 9 hens per square metre of indoor space. If I'm reading correctly, this applies to both free-range and barn hens. Free range hens also need outdoor space at a density of no more than 2500 birds per hectare, which works out to 4 square metres per bird (although 1 m2 is allowed for birds under 21 weeks old). That's also the EU rule for 'free range' eggs. The RSPCA spec is about 100 pages of details about popholes, lighting, water, and so on. Whether it's effectively enforced, I can't tell, but it's not a joke. Edit: My bad, the Guardian article also says 9 birds per square metre for free range eggs. Free-range chickens raised for meat can be kept at a higher density than laying hens: 13 per square metre indoors and 1 square metre outdoor space. But eggs are the topic here.