Happy Hens
Something to think about— Egg-laying production facilities keep the air temperature around 75. Ventilation fans are controlled according to indoor temperature. A side note—Hens would be even happier if those companies used "enriched/furnished" cages!
I would seriously doubt that temperature maintenance in commercial farms has anything to do with the hens' happiness and more to do with keeping them in production year-round. They're looking at the bottom line, not the comfort of their birds, or otherwise those enriched cages would be more common--or better yet, they would actually give them a reasonable amount of space in general. It's the same reason they keep their birds under constant, dim light as well, even though numerous studies have found this to be VERY unhealthy for them. I've been researching different conditions caused by heat lamps and their effects on chickens, particularly pertaining to use in brooders, but as production is the main concern when it comes to most of these studies, many of them relate to egg-laying adults as well. Come to find out, constant, continuous lighting, both in the brooder and later in life, increases aggression among birds, messes with their productivity (actually reducing future productivity if used early in life, but increasing it later on, depending on the conditions), and causes eye damage and abnormalities with such consistency that chickens can reliably used as an animal model for studying glaucoma and other conditions of the eye. Yes, you read that right--
continuous light such as from heat lamps consistently causes eye damage and abnormalities in chickens, particularly in growing chicks. Anyway, point being, I would question the motives for anything that commercial farming does, personally, considering most of it is geared toward squeezing as much money out of these birds as possible in as little time as possible.
Differences in broodies:
The blue orp went from normal to broody in 48 hrs, but the silkie took a few days. The silkie spent longer in the nest box & was grouchy when laying. After 1/2 a day, she'd hop out & sleep on the roost at night - only to return to the nest the next morning. Neither hen will peck toward my hand if I pick up their chicks or eggs. However, the blue orp makes very scary noises & long attack screams and the silkie only a gentle 1 sec grumble.
This is exactly how my Silkies are when they go broody! It's never a quick thing with them, they always build up to broodiness. They start off by lingering on the nest longer than usual for egg laying, then start grumbling and sitting longer, then they sit all day and go to roost for the night, and then finally they go full broody and I find them in the nests when I go to close the coop for the night. Maybe they think if they approach it slowly I won't notice?

Mine also don't do the broody war-cry that every other broody breed I've owned does, only grumbling a bit if I disturb them. Nothing compared to the little silkied Cochin bantams--those girls produce this wicked, sustained SCREAM if I even look at them while they're brooding! But the Cochins also go from 0 to broody in a day if they feel like it, hence why Donna is currently residing in the broody buster after being totally normal since her last broody stint.
Lacing, Double-Lacing, Penciling, Partridge, etc. As Faraday theorized, it's color-related. Genetically, it's sort of a stacking effect. First off, Partridge is the same as Silver Penciled except for that Silver Penciled has the silver gene active to turn all gold / brown areas white. These guys are both based on eb ( 'partridge' ) and have the 'Pattern Gene' Pg. Add to Penciling the melanising gene (Ml), and you get Double-Lacing. Basically, this just thickens the penciling. Add to that Columbia restriction (Co) and it pulls all the black to the edge, giving you single lacing. Sebright lacing is different than that seen on Orps or Wyandottes in that it's based on 'Crow Wing' ER rather than 'Partridge' eb, and it adds 'Dark brown' Db to the mix as well. So, in other words, the most simple looking out of all of them has the most going on behind the scenes.

This is just what I've gathered from tinkering with the
Chicken Calculator, so anyone feel free to correct me if I'm way off on anything!
Interesting note on Partridge--sometimes wild-type coloring is referred to as Partridge as well, just in case you weren't confused enough!

For those unaware, wild-type partridge looks like this:
Sebright lacing tends to be a bit thinner or less dark overall and goes into the tail feathers, as compared to Orp or Dotte lacing, which usually is darker and has a black tail.
Anyone need a drool cloth or smelling-salts yet?

I had a long, miserable weekend and a test today that I had no clue how to study for (but it was open book, open note, open internet, so it went pretty well anyway), so delving into chicken genetics was a nice way to unwind from all that.
