If you go the backyard chickens forums and do a search there are several pages put together of what is acceptable for chickens to eat and what is not.
You have to be careful when you feed them weeds, only because there have been cases of a chicken choking on them.
They usually only break a piece at a time off when they are out foraging but when you throw them big long pieces sometimes they keep on eating it down and they get these big long pieces stuck in their throats or it causes their crops to get bound up.
Anytime you feed them table food you must give them access to a bowl of grit to help them grind the food up in their crops.
There is also some foods that can cause the eggs to taste funny so you have to be careful of anything to strong.
I tend to keep the girls on their food, which is the Purina Layena crumbles and then let them roam around the yard.
I keep the scraps to the very minimum.I want to make sure they are getting the vitamins and minerals meant for them in the chicken feed.
I do give the yogurt plain or vanilla a couple of days a week to keep their digestive system healthy. Its very good for them.
Chickens also need to have oyster shell available( I mix it in with their food) so they have nice strong egg shells.
The only trouble with those sexlink types, and I do have some and they are great, is that they tend to burn out sooner since they are born with all the stores of eggs they will ever lay and they develop reproductive problems, usually prolapse and getting egg bound.
The usual standard for housing to birds ratio is 4 square feet per bird unless you raise bantams and then you can get away with 3 square feet.
They also all need enough room on the roost/perch, they will all need to roost at night.
They do need room to go out in forage so either a run or a place to free range is needed.
The breeds that were mentioned are nice, I have them all. If you like the colored eggs I suggest a marans breed, the most common and most affordable is the cuckoo marans and they lay a very dark speckled egg.
The black copper marans lay the darkest eggs but they are extremely expensive right now.
The blue egg layers are the auracaunas and the ameraucanas but most people have a mutt of the mix called easter eggers and they just don't realize it. They are very hard to tell apart sometimes and if you buy them from a hatchery you will absolutely be getting an easter egger, they advertise the pure breeds but they don't really have them.
The two pure breeds I mentioned should only lay blue eggs, but many times people purchase these and then the hen will lay a green egg or a pink "ish" egg.
Its still possible that you can get one that lays a blue egg as well but I just wanted to make you aware that you could end up with a green or pink egg layer.
The easter eggers are usually much prettier since they have a wide variety of colors compared to the basic pure breeds.
The green eggs are still very pretty and quite large. I have a couple, one lays green eggs and one lays a bluish egg not as robins egg blue as the ameraucanas lay. Mine lay every day and are sweet girls.
Both of these girls were sold to me as "ameraucanas" which they are obviously not by the color of their eggs.
I have golden lakenvelders that lay a white egg every day, smaller than the standared layers but nice and consistent.
I had leghorns and couldn't wait to sell em off, which I did as soon as I could, they were very high strung which I have now heard is their nature.
Well hope some of that helped, good luck with everyone who is just starting out with the chickens.
You will love having them.
We went away for an overnight stay and my 6 year old son was upset because he missed our chickens. You get attached to them .