My experience with chicks is very small, I let two hens sit, a year apart from each other, with eggs from a neighbour. From the first hatch, two of the three pullets, Merle and Léa, are very often broody, more or less once every six weeks. Merle, like Mow, started thinking about sitting as soon as she began laying : I thought she had parasites because she was plucking her feathers out and dustbathing all the time. A few days after she was broody !Personalities come into it too; despite being a real heritage breed, and now in her 7th year, Venka has never gone broody - yet she has lots of kids running around here (some that look just like her and some more obviously hybrids), thanks to other hens in the flock doing all the nurturing work for her. I think some hens are smart enough to reproduce their genes without effort beyond laying the egg, like a cuckoo, being quite happy to see others playing broody and raising their kids for them.
This year's hatch, none of the four pullets have shown the least inclination to sit. They have been laying for three months by now and the winter is exceptionally warm, whereas it was exceptionally cold last year. They were raised by Léa, who is actually broody right now, in the exact same environment, apart from all the changes we have no control over like climate and chicken relationships.
So my small experience tends to make me think either personalities or genetics do play a role.
I need to read the article more in depth before reviewing. Two details I wondered about. Recommended quantity of feed here is 100 grams daily. Not 150 or 200. As far as I know, while we don't have pellets here, there isn't a great difference in the type of food available, so I wonder why that difference.Getting the message that chickens do not automatically send all ingested feed to their crop is quite difficult to get accross. Most people assume that all feed enters the crop.
Getting people to understand that it is the way one feeds chickens that determines what get sent to the crop is even more difficult; a constant supply of feed is likely to give minimum crop use. Meal time feeding tends to promote crop use.
These points and the time taken to digest various feed types have implications for the crop full at night, empty in the morning test advice.
The other point is about hard things not being an issue for digestion. I've had the experience many times that chickens will leave out things that are both hard and too big. They can for example tear apart a whole apple : but they won't eat a whole nut or the bigger squash seeds if they can't manage to break them. Are my chickens impaired or is this something true for all chickens ?