What do i need to consider?

No hoildays unless you can get some one to look after them. 
Building a Run DO NOT PURCHASE CHEAP Chinese runs as they are far to small and will not last.
Getting up early every day and letting the out or you can pay £90 for an auto opener and closer.
Paying for vet fees.

Loosing a fair part of your garden to chickens. I would suggest 2-4 meter squared per chicken though the bare minimum is 1 meter squared. 

Worrying about them, there poo and when are they going to lay......

On the plus side you will have 1 eggs a day for 18months - 3 years max with a hybrid chicken or less frequent and for up to 6 -7 years with a pure breed chicken

Not wanting to put you off. 
Have a look here.... http://chat.allotment-garden.org/index.php?topic=1688.0

Are you getting them as pets with eggs as a bonus or do you want them because you want lots of eggs. How many are you thinking of having? They are great characters and easy to keep but there's a lot that could go wrong so you need to be prepared.

Agree with everything above.
Read up as much as you can and make sure you have everything in place before getting the birds.
Choose a breeder who has been recommended by other chicken keepers...there are pages on here.  A good breeder will be able to give you lots of practical, hands-on advice, that may not be in the books you have read!

Have a firm idea of how many you are going to get, it is very easy to go over board when faced with lots of pretty birds!!!!  I was going to get 3, (we got 6 and have just hatched another 5 chicks!) 

But most importantly, there is no turning back...let a chicken into your heart and you are lost!
 

Colette x

Hi, getting chickens was one of the best things i have ever done, but.....
you need to do your research, you need to know your way around a hen, what they need to eat, the living conditions, the illness that commonly(sp?) affect them.
you nee to decide why you want them...is it meat, eggs, or pets?...what do you want to do with them when they stop laying...are you quite happy for them tp live out their retirement with you?...its fine if you want them for meat/eggs, but the reasons you want them should help you decide what breeds of bird you should be looking at. Some birds are not good layers, some dont have a lot of meat on them, some are not as friendly as others etc etc, so deciding what you want from your birds is a big start
housing, i would build it myself, or find some one to do it for you, the bought ones are rarely any good! they look cute and twee, but they fall apart after a few good rainfalls, and they never house the amount of chickens they say!  Omlet do some lovely plastic ones. they are very expensive, but if you take into account how long they will last, and all the chemicals and wood preservative you will buy, its probably not that bad!

I let my girls free range, and they have trashed my garden! . i still have grass, but no flowers, veg....and the soil is all over the paths along with loads of chicken poo. so this winter we are taking some of the garden back . if you dont wat them to free range, build a lovely big run, with lots of things for them to do .
you ned to find a vet....not all vets know about poultry!
and lastly you ned to find someone you can trust to step in if you cant...i.e emergencies, holidays etc
this forum has so many people who will be happy to help. they have been a godsend to me and to many other people, so if you need help, ask, there will always be someone who knows the answer!. hope you enjoy your chickens, they really re fab!

I just wanted to add that I was completely new to chicken keeping and we've now had our ex bats for 7 weeks...we have never had other pets or children and what started as a cheaper way to get eggs and an idea of living the good life has turned into the best thing I have ever done - but also one of the most time consuming (how many times do I find myself just hovering by the window watching their antics with a cold cuppa in my hands??!) and worrying too...however this forum has been fabulous for any worries/problems and to find there are other chicken huggers out there too!  I would thoroughly recommend keeping chickens if you have the time, space and money to set them up properly...
Cattin