I know that CraftydramaQueen, is thinking of getting chickens, and so I thought it would be good, and maybe helpful to others to do a “I wish someone had told me” post!!!!
The first thing to say is that chickens are really easy to keep. Food, Water somewhere warm to sleep, and maybe some grit is really all they need. But here is just a tad more detail!!
House
You can buy houses on eBay and lots of websites. My advice is probably to get the cheapest thing you can find!! WHY? well in 2 months you’ll want more chickens and whatever you bought won’t be big enough, and you’ll have realised that you can make something just as good out of bits and pieces and although it might cost the same it’ll do exactly what you want, rather than having umpteen features that just don’t cut it for you. Many people use sheds, and I have come to realise the common sense in this. I don’t have one, I have two houses….. but sheds are definitely the way to go. You can get in them standing up, which helps with the back ache while cleaning the endless amounts of pooh (especially in winter when they spend so much more time in the house) It should be noted though that if you use wood for your house, you will almost certainly get red-mite in the summer months. There are numerous remedies, some work…. many don’t. Personally I find a blow torch pretty infallible, and cheap! but obviously there’s only so much blowtorching a wooden house is going to take (and it needs to be done once a week during an infestation) so that may need to be taken into account when you select your house/materials (Other redmite treatments include a steamer (rather than blowtorch) diatomaceous earth, barrier powders and there is a redmite killer powder though i can’t find the name of it at the moment. Old fashioned creosote works too, and I have heard that jeyes fluid does as well) Redmite live in the crevices and seams of the wood, so the fewer joins the better – houses made of tongued and grooved wood will potentially have more places for the little blighters to hide. This is why the Omlet houses are popular, – made of plastic they are less likely to harbour redmite. Redmite only come out at night and feed on the birds. Your birds will soon show signs of infestation….. bald bottoms and a general aversion to going in the house are good indications that something isn’t quite right. If left your birds can become quite ill, but it’s not too much trouble to keep them at a bay, or at a manageable level.
The house needs ventilation so you don’t get condensation, but not too much in the way of draughts. Having said that both my houses are doorless (I don’t use pop-hole covers) and I haven’t had any chickens with colds!.
Your house needs a perch for them to sleep on, and a nest box for them to (hopefully) lay eggs in. Perches can be made of 2” x 2” or 2” x 1” wood, rounded off on the corners, but I have known plenty of others use branches and all sorts! Nest boxes can be anything from crisp boxes, to lovely add-on side boxes. Your nest box needs to be as dark as possible to encourage laying in it (as opposed to anywhere else) and to discourage egg eating. You can put as many nest boxes as you like, but I’ll bet they all queue up to use the same one.
If at all possible it is worth investing in a small additional ark/house/ hutch anything! It can be used for quarantine (see chickens below) or a broody pen (should you wish to hatch) or a hospital should one of you chickens need a breather from the others!
Chickens
What chickens to get?? Your main choice is pure breed or hybrid. My first were pure breeds, and I have to be honest and say that much as I love them, I wouldn’t spend that kind of money on chickens again. They were £30 each, and lay around 7 months of the year, from about March to September. Obviously this is different for every breed, but pure breeds generally will lay this kind of amount 7 – 9 months of the year. Hybrids (a cross of 2 breeds) will generally lay much longer in the year, and will be cheaper to buy. My hybrids were £6 each…. one of them has laid most days for 2 years now, the other moulted this year and took around 5 weeks to come back into lay. For egg production these are the little beauties you want. Many of them have “breed” names now. Warren is the one I have which is a Rhode Island Red x Light Sussex. The problem with the pure breeds is that you are still feeding them throughout that period of non-laying, so the cost per egg goes up considerably. I know that is not the only consideration, but money does have a bearing and is worth pointing out in the overall picture. Obviously these are only my suggestion/observations. But I do wish I had known more before I spent £30 on the Welsummers!
Also, when you are first buying chickens it is thought it wise to get 3 or more, as if anything happens to one there will always be company. Chickens are social and shouldn’t be left alone :(
Should you need (or just want!!!!!) to add to your flock, new birds should be quarantined for at least a week and preferably 10 days to make sure they are not bringing any illnesses into your flock. It also gives the new birds time to get used to your soil/environment and anything they may need to become immune to before mixing with your flock.
Bedding
In the house you’ll need a bit of bedding, otherwise the pooh will rot the house!!! I use whichever horse bedding is going cheapest. Proper straw doesn’t really work as the lengths are too long to pick the pooh up, and you end up throwing the whole bedding away every time you clean, which isn’t really necessary. At the moment I am using something called Easybed, which is a dustless straw and broken down into lengths about 2 – 4 inches. Nice and manageable. You can also get wood chippings. Hay shouldn’t be used as it harbours a fungus which can be harmful to chickens, and the same goes for anything with Bark in it. For economy you can use shredded paper, but it has it’s faults. In the nest box it sticks to the eggs as they come out a tad tacky on the outside, and in the house it gets a bit wet. But it has it’s place and if you have the time to clean every day then it’s a good choice.
Run
I believe the suggested minimum exterior space for chickens is 1 sq m per bird……. but in all honesty if you pack them in that tight you’ll be knee deep in pooh quite quickly! I have 5 birds in a 3m x 4m run, and that seems to be a good size. I could put a couple more birds in there quite easily. The floor of my run is just earth. I am lucky in that my soil is free draining chalk, so generally in all but the wettest weather it is fairly dry and clean. I turn the earth over shallowly/roughly about once a fortnight. And once every 4 – 6 weeks turn it over quite deep and thoroughly. In really wet weather I add some bedding material on top to give the birds something cleaner and drier to scratch in.
Other recommendations for runs are to use gravel – not pea shingle, but large gravel (I think 20mm size) This can be pressure washed and disinfected easily and I know a lot of people that use it to great effect.
You can of course put them on grass……. but it won’t be there for long! 
Food
Layers Pellets are all that are needed! Around £5 – 8 per 20kg sack from a feed merchant (horse feed places usually do poultry food) Layers pellets are a complete food and the birds don’t “need” anything else.
However,
If you also buy a sack of mixed corn, the birds will soon learn to come to you/feed out of you hand/ do somersaults (ok the last one was a lie) But they really do learn quickly for corn. it’s a great way to gain confidence….. scatter on the floor at first….. feed from a pot…… feed from your hand….. use to get them to bed by placing just inside the house doorway, or even a few pieces on each rung of the ladder if you use one… Treat it like chocolate though – not too much! It’s a treat. I put a handful down most evenings on the ground for the birds to scratch and find. In winter they can have a bit more as it does keep them warmer as it digests much slower.
Finally, it’s worth putting a grit pot out. Again you can get grit from a feed merchant, really really cheap! and worth having around. The birds use it in their crops to grind down their food, and also the calcium in it helps with egg shell production (if you get soft shelled eggs, add a bit of grit to their layers pellets) It’s just a couple of pounds for enough to last a year or so, they don’t need much but they do need some! Technically I don’t think they need it with layers pellets as they are supposed to be complete, but mine tend to lay soft shells if I don’t have it around.
Food/Water Vessels
Because chickens scratch for their food, almost anything you put the food in will end up drowned in bedding/earth/pooh and the food will be scattered everywhere. If you are leaving your chickens with food all day (which is the usual way) buy a feeder with a scratch ring. or pop a bit of mesh over the food and secure so they have to peck through it. Or use a hopper which attaches to the side of the run. If thinking about being frugal then you could probably use a plant saucer for a few hens or a trough for more but I would definitely suggest the mesh!! Also worth just lifting off the ground a little – again to stop them scratching the dirt into the food. A couple of bricks or something similar is fine. Personally I use this setup with the added scratch ring and stand, but it’s quite big so you may want a smaller version for a small run. (and they still manage to spill a bit!! – love ‘em)
Water is pretty tricky too, I have found the best things are little gizmo’s that use old soda/wine bottles. This one is quite good , but again it can get filled up with dirt/straw etc. These are the ones I have found the best for manual drinkers. I keep a few around in case my other bits and pieces break or anything – they’re great! If you want something to use for more birds or like me are a bit too lazy to fill bottles every day (yes you heard it here folks, I am the laziest person on earth) Then I use an old water butt, with a tap, hose and connected to a tray. You’ll also need a T connector as I remember! There are loads of alternatives to this particular set up, but it’s so easy and worth doing. Also makes it very easy if you are going away for a day or three, as although it’s helpful for neighbours to pick up the eggs, there’s no reason for them to worry about water or feed..
Vermin
One thing that is likely to turn up soon after the chickens are the mice. Keep all food in an old lidded dustbin if possible and keep your eyes open for signs of vermin. - Just don’t give them too much in the way of free board and lodging!!
I’ve tried to cover the most often asked questions in the above really. And if you’re still reading then congratulations on your concentration level! There follows a quick summary in case you got bored!
You will need:
House and Run - buy as cheap as you can, your first one will never be big enough or you’ll want to change it soon.
Feed – layers’ pellets, corn as a treat.
Food vessel – with a scratch ring/plate
Dustbin or similar to keep food in
Water vessel – ones that attach to the side of the run are best (You can also use cut up old plastic milk bottles tied to the run wire)
Grit and something to put it in
blowtorch or steamer or one of the redmite powders (none of the powders I have tried have been totally successful – blowtorch is infallible!)
bedding – straw or woodchip. It’ll last a long while if only used in the house and nest boxes.
Egg boxes!!!! 
Plenty of batteries for your camera!
. So all the others were promptly put back, and today one has chipped. Seriously it’s day 26, as far as I know the latest any of my Poultry sages has ever heard of is day 25………. I am a wreck! I also now know that I should dunk the eggs in warm water before giving up on them, and they dance if they are still alive…… well three more are dancing, so in theory they could be still going to hatch. I’ve counted and re-counted the days on my calendar wondering if I could have been stupid enough to have missed a week (it wouldn’t surprise me I am not the most day/date aware person in the world – apart from the 19th of every month when the tax man needs paying!) but I am definitely right – starting at day 0 (to allow for Ma Hen to warm up the eggs) today is day 26! I don’t know if they will hatch – I don’t know if the membranes inside the egg will be like shoe leather by now? but I know that my nerves were not made to take this kind of stress!!! G & T anyone?!