Hi there

It depends on what you want your chickens to be like really: good egg layers, pretty, friendly etc... it may be an idea to go to a breeder (make sure they are reliable) and ask about which is the best breed to buy. You have to understand that also if you get a cockeral, (depending on where you live) your neibours may not be best pleased if it is up crowing at 5 am.
The best sort of feed is just a plain layers mash which can be bought from certian farmers and has all the nutrients they need although chickens love any vegetable scraps you can give them.
The best type of cage is a rabbit like hutch with a run connected onto it so that they can be tucked away in the hutch at night and allowed into the run during the day.
If you are interested and not too bothered about how your chickens will look, there are many ex battery hens in need of good homes and once they have settled in they make very friendly chickens.
If there any more question, feel free to ask

Have fun choosing!
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Vixen
My Zoo!!!

Polo, Pepper, Solo, Bullet, Trigger, Bandit and Gem

About 50 of them

(rats) Ebony and Sotty
(Chickens) Persephone, Penny, Pandora and Pansy
Giant Afircan land snails