At some point you will need to build some kind of structure for your chickens to live in. The sky is the limit in terms of price and design (some coops are better than my house!) but poultry housing does not have to be all that expensive – especially if you have the skills to build yourself. Making a coop for your chickens is an ultimately satisfying practice that will eventually bring you some lovely free range eggs.
Chicken coops can be relatively simple to build (compared with a house anyway). If you have a few backyard chickens then a small chicken coop design such as an a-frame coop can be enough and those kinds of smaller coops can be fairly simple to build with basically some 2x4s, strong wire and a heavy duty staple gun. If you are lucky enough to have access to some scrap lumber and are not too fussy about following the exact design then you can adapt most plans to what you have to hand and make a coop very cheaply. With many chickens you would probably need to construct some kind of large shed which would obviously need more advanced skills (and tools). There are plans for chicken coops widely available which can be followed if you are competent at DIY (do it yourself). We have a chicken coop plan available here which will give you an idea of the sort of project you will be taking on if building your own coop.
One thing to bear in mind before starting any of the actual construction is to make sure that your chicken coop is going to be located in an area that is both safe for the chickens and far enough away from your neighbours. The legislation regarding this may vary depending on your geographical location.