Well, yes, if you haven't kept chickens before at your house, there will be a lot of planning to do first. They will need a secure, waterproof coop of a suitable design, and an enclosed run which is safe from predators, even if you intend to let them roam the garden when its safe for them to do so. Chickens do need a lot of space, the run has to be a minimum of 2 square metres of floor space per bird, as they may fight, peck each other's feathers, and cause bullying and stress if kept in too small a run. There will be times when they have to be in the run, especially in winter, when you are out, and after dark when foxes and other predators are around.
One of the advantages of quail is that you can keep them in a very small space. I keep three coturnix at a time in cages 3 ft by 2 ft in winter, and I could keep up to 4-5 in that space. In summer I give them a 4 ft square rabbit run on grass, which could hold up to 16 birds at 1 sq, ft each, though it don't keep that many in there. Quail are not so high maintenance as hens. With hens you have to clean out the coop every day, pick up poo from the floor of the run, and find space for a dustbin full of chicken pellets plus a lot of other equipment. Yes, keeping hens is a great hobby but setup costs are high and you need to think carefully about what sort of birds you want and whether they are mainly for laying eggs or else because you just enjoy the look of a particular breed. Lots of help on here though! However, if you do want hens it would probably be best to but them at point of lay, ie at about 16 - 18 weeks old, ready to lay in a few weeks. That way you can be sure of buying hens. If you hatch your own you will end up with 50% cockerels that nobody will want unless you are prepared to kill and eat them.