With the enriched or furnished cage system, what they've done is ask what the reasons were. If you go back far enough, birds weren't in any form of cage. They were on the ground. They actually came off the ground into cages as a way of managing disease, managing cannibalism, and ensuring that all birds got adequate feed and fresh water. There were strengths to that, but the compromise was space and some of these natural behaviours.
The design is effectively one of giant colonies. There are cages which hold about 60 birds, with probably double the amount of space per bird. Running the length of these long colony systems there are perches so the birds can perch. If you go back far enough, the commercial fowl we use go back to jungle fowl. Those birds instinctively will go up into the trees at night. That's the instinctive part. Birds prefer to come up off the ground at night and they'll perch. They're comfortable doing that.
Also, by choice, if they can, rather than just laying their eggs in the bottom of the cage, they would go to a secluded area they deem to be safe to lay an egg. There are these little strips of curtains that allow the birds to go into a private place to lay. You'll actually see the birds queueing up to lay their eggs, to get into this nest area.
The third natural behaviour is one I think Dr. Widowski will speak to, because she's done a ton of research into determining how much energy a bird will expend to engage in certain natural behaviours.
The other is scratching or dust bathing. There is a little rough-surfaced pad which the birds will scratch, and they'll put a little bit of feed on top of that.
On that chart, the reason some of these things show up in yellow and not green is that when you have this scratch area, you could get some manure buildup, so you could get some compromise on bird health. It's minimal, but it is a risk.
What they've tried to do is marry the strengths of different systems into one.
What the enriched or furnished colony cage still does not do is allow the birds to forage far and wide, as they would if they were free run or free range.