Let me get this started. We used to raise about 200 birds a year for meat and then have a few egg layers as well.
For a pure meat bird - Cornish Rock Cross - fast growth and good feed conversion. We used to take the hens out at six to six and a half weeks as they would dress 5-6 lbs and would only add fat after that age. The cockerels would keep on growing and we took quite a few of them to ten to eleven weeks and dress them at 10+ lbs. Used them as roasters.
Feed - special mix only. High corn and soybean meal concentration with a special premix that is high in Vitamin B and minerals. One of the biggest issues with these birds are keeping their feet under them. They grow so fast that often their legs do not keep up and this is a feed issue. Talk to the feed mill and if they hem and haw a little about what you need move on. Once they start going down you are in trouble as their is almost no recovery. Also add a vitamin B stress pack to the water for the first couple of weeks - very important in keeping the death rate down.
If you buy a feed at TSC or somewhere like that it will probably have antibiotics mixed in as they make it simple for them and their buyers but it is not organic food.
The other trick we used was to buy our chicks late - usually early July. Little chicks like it real warm 90+ F. I never did understand why people bought chicks in March and April and then have death loss due to the temperature in their area falling into the 80s. Plus the big chickens do not handle heat real well so if you buy in early to mid July you should be by the bad heat before they are too big.
I used a small shed that housed them until they were about 3 weeks old and then I had a pen with a roof over part of it. The pen was fenced in with Poultry fencing (looks like woven wire but it is about six feet tall and has very small holes at the bottom. The poultry netting was too much lightweight and too much trouble to keep up. I did have owl problems one year so I started putting a nylon netting over the open area to keep the owl out. One year we had a great horned Owl visiting us about every other night and he would kill 5-6 birds each time he visited. Very frustrating. Put the netting over and he still got in but could not get out. I pulled the netting back and let him out and he never came back again. Pretty amazing to be within 10' of a bird like that. Very scary as well.
You need to make sure the fence is tied down to the ground as varmints are good at pushing under it. Think skunks, raccoons, mink, etc. I usually laid landscape timbers all the way around and stapled the bottom of the fence to them.
Also, the Cornish Rock Cross do not need a roost. They have a hard enough time getting from the water to the feed. In fact I found out the hard way one year when I moved the water too far away from where it had been because it got muddy. They didn't drink for two days because they could not find it.
Another option would be to purchase a dual purpose birds like the Rhode Island Reds. You can let them run for the day and let them back in at night to roost. If you are only going to have 12 or so you could build a little roll around coop with a wire mesh floor for automatic cleaning. Just move it every day to keep from killing the grass. They do a wonderful job on bugs but they can be kind of hard on a garden as they like tomatoes and other vegetables real well. With this breed they do not grow near as fast and you do not need the special feed. In fact you can feed them your kitchen garbage and they will love it. Cucumbers that got too big, rotten tomatoes, etc. If you want to have some fun throw some potato bugs or japanese beetles in their pen. These will nto get as big but will be much easier to raise. My daughter kept one rooster as a pet for a few years - he was a fun one and would come to the house looking for her - literally going around the house and looking in the windows and peck at the window when he found her. Another fun sight was the day that four chicken hawks descended on my flock out running around the yard. The hens took cover and the cockerels came out to fight. I saw them knock one chicken hawk right out of the air and attack it. he got away but they all left and didn't come back.
hope this helps!