Chickens are such characters and are so attractive that it is easy to fall in love with each and every breed!
When deciding on species and systems of management, you need to first be clear about your aims. Are you interested in keeping chickens for profit or self sufficiency, or whether you want to keep them purely for the pleasure of doing so? You also need to ascertain how much time and space you have at your disposal.
SpaceThe theory behind keeping free-range poultry is wonderful but the practice is not always quite so simple. While many people's ideas is to have chickens scratching at the back door, picking at scraps and living a contented life, in reality things can be very different. Although they will eradicate inspect pests and slugs in the garden, some of their habits are less welcome! For example, our vegetable patch is opposite their coup so in the afternoon they graze there and as a result we have no melons this year (they ate all the flowers) and they are eating the strawberries and raspberries too (as we have plenty to go round we leave it but ideally we should have fenced this off and is a job on the to-do list!
Chickens and bantams love nothing more than a good dust bath to help rid themselves of parasites, and consider a well prepared seedbed ideal for the purpose. Our chickens dust bath every morning when we let them out to free-range, we do not stop our chickens from going anywhere in our garden, they even come on the terrace and in the kitchen if we leave the door open, fighting to get to the cat food which I now make sure is not left out! Our chickens dust bath is in the small garden we have outside the front door, as I have nothing planted here other than fir trees we do not care but every night I do have to sweep up the dirt they have shaken out of their feathers!
To a chicken's mind bark mulch that has been carefully placed is scratching heaven so think about that while you plan their area.
For the above reasons you may wish to keep your chickens confined to a run, a run will also prevent your hens from laying in the shrubbery, however, this has never happened to us, they like their hen house and lay in the same place every single day, if they are out they go back to their house to lay. When you first get your chickens keep them locked in until midday to enourage this - we didn´t have to but some people have had hens laying all over the place!
The amount of space needed in the run depends on whether your chickens can be given some free range, but generallyt a run should be as big as is practicable.
Chickens & The GardenChoose bantams with feathered legs such as Pekins, as these don't, or can't, scratch up the grass on your lawn quite as much as other breeds.
Lay chicken wire flat on your herbaceous or annual beds in the winter. The plants will grow up through the wire but the hens won't be able to scratch then up.
If dust bathing in your beds become a problem, you could try tempting the chickens away with an irresistible box of dry sand or peat.
Choosing a RoosterThe co ckerels of some breeds are more aggressive than others, so it may be wise to avoid these if you have young children. Generally, the males of the heavier breeds such as Maran, New Hampshire Red, Orpington, Plymouth Rock, Rhode Island Red and Sussex are calm, placed and friendly. Extremely heavy breeds, such as Brahma and Cochin make good pets but they may be too big for children to carry them around. If that is the case Bantam varieties if these exist in Spain.
As for choosing the girls, it would be easier if I knew your intentions so I can help further there

Simone