A lot of people are keeping hens now, 5 or less can be classed as pets, but do have a word with your neighbroughs as a lot of people have found neighbroughs can complain.
If they say about the noise tell them you wont have a boy just girls they dont make such a noise. Also say you will sell the spare eggs it is hard to get fresh eggs.
Clean them out on a regular basic's the stuff can go into the grey bins for recycling.
Store their food in bins with lids so rats/mice cannot get to it.
If you have them pen in runs cats/foxes cannot get to them.