Just understand any homestead chicken breed that are raised for meat & eggs, like Rhode Island Reds, Orpingtons, Sussex, etc will never provide the same amount of meat as the store bought. Those are a hybrid Cornish X that are specifically bred to reach butcher size in 6 to 8 weeks, with plenty of plump meaty carcass. They start out as the same size of a regular chick, but within just a few weeks they become huge, lazy and only eat, sleep & poop. Literally. By the time they are 6 to 8 weeks (normal chicks are still fairly small and fit in your hand), they need to be butchered. If left much longer health problems can start like broken legs that don't grow as fast or as strong to hold the weight of their bodies. Heart issues, etc Even if you let the Cornish X's forage early on so they grow out a bit slower, the outcome is about the same. They are eating & pooping machines.......but it is a quick turnaround to get chicks to the freezer in just a couple of months. At butcher time, they are around 5 or 6lbs of meat each. So if you raise say 20 birds for the freezer, in 2 months time you'll have about 100lbs of meat......but to do that, they need lots of protein and is much easier by feeding bought feed specifically for them. They will eat as long as food is available. Some people provide feed 24/7.......some only feed them twice a day and let them forage for the rest. This is what I've done, with a chicken tractor to move around the yard for forage. Personally feeding 24/7 is more of a waste and asking for health issues IMHO, but everyone does things differently.
As for homestead chickens, they grow out much slower and can take up to 6 months to get of good size, but they're still skinny in comparison. Do some research about breeds, characteristics, size, butcher weights, egg laying, broodiness/mothering ability, etc and decide on which one works for you and your plans. You'll need 1 rooster for about every 8 hens. Maybe more, maybe less, but that would work.
Do you have an incubator? Or would you rely on a broody hen to do the work for you??? If you only have 1 flock of birds, how long do you plan to keep that flock? Do you plan to only butcher any cockerels and old hens?? It is possible to only have the one rooster and have him breed several generations of hens, but eventually you will need to change up the genetics before you get some oddities. My understanding is to never let a full blooded brother & sister mate as that can get you 2 headed monsters. Either way, it's still a good idea to add some fresh new DNA every couple of years.
As for feed.......chickens will eat just about anything, including styrofoam, bb's, plastic bits, broken glass........you name it but the same goes for foodstuffs as well. I have known some people only feed store bought feed, some people offer store bought & forage and others don't offer any kind of feed, leaving the birds to fend for themselves......all the chickens survive just fine.
You can grow grains, most any kind will do, but do have more nutrition of the grains are sprouted first. Put some in a jar and shake it up with hot tap water, then drain.......next day rinse & shake with hot water and drain. Keep doing that for a few days and you'll see the grains sprout. Feed anytime after that. You can also feed them leftovers & kitchen scraps, garden leftovers as well. Just don't feed raw potatoes.......or atleast that's what I've heard from different people and about different livestock animals. Cook them first, but never raw.
Just whatever you do, do not use chemical weed killers or fertilizers or the like on any ground or pasture you let the birds on.
