Maybe I lived in a bubble, but I never heard of laying crumbles until I was out of the army and built my house.
my wife grew up on a small farm and I asked her what her parents fed their chickens. "Oats" and they did not get the idea from any movie..
If any of our neighbors fed special boughten feed , I was not aware of it.
I did feed baby ducks crumbles when I was a kid. that was in the mid to late '50's.
I used to raise 200 meaties each year back in the mid 70's. they got 50/50 finely ground corn and oats none of them ever died from heart attacks or crippled themselves from overeating. I even kept some of the hens and they layed eggs for me through the winter..
I do not raise chickens for pets. if there is a freeloader, she goes into the soup pot.,.
......jiminwisc......
Naturally, chickens will survive on different management styles. If you eat yours, then it longevity doesn't matter that much to you as it does to us, so if that works for you, then that's fine. We have ours for table eggs and hatching eggs for our rare breeds, and most all become pets, too. Right now, some are coming back into production and we have one new layer. Two hen laying now are 7 & 8 years old, one is almost 11, two others are 2 & 4 years old. We still have to buy eggs, but hopefully, not much longer-the Brahmas seem to be almost over their molts and it was their first big one.
I have to correct something I said--I believe my dad said Granddaddy fed laying "mash", to be specific, which of course, means crumble. He was born in the late 1800's and he bought it back then, so it was available, for sure. He raised broilers for some company, too, though, so he may have had more information than some folks and he had to buy feed for the big chicken house that was beyond what a backyarder would.
In a case where commercial feed could not be purchased, and trust me, we have discussed this here many times in regard to an SHTF situation, mine would have to spend much more time out free ranging than they do now and I would not be keeping separate breeding groups because they'd all have to be out there together in order to spend enough daily hours foraging to get more sustenance. When we had the original flock and only one rooster, they free ranged much of each day, though back then, we did not have any pasture or grasses growing (all woods). We'd have to go back to that management model. Never had any issues with hens laying anywhere except in the coop, even back then.
We raise rare breed and rare color variety chickens now, some heritage line Barred Plymouth Rocks like Great Grandma had, some import color Brahmas. In the SHTF situation I just mentioned, no more separation of breeds and the Brahma rooster would have to go or when he passed on, not be replaced, sadly, because he's just way too large for most average size hens. Ours all end up being pets in addition to breeding stock because, well, no mean roosters here. And I have hens who are almost 11 years old, too. No one is eaten and won't be unless there is a rare aggressive rooster. No problem eating one like that, and we have, it's just been a long time because we breed for temperament.