Beekeeping is a great way of getting something for nothing.......
Green animals » pigeons
Squabs, or the young birds are good to eat. I do remember eating one in Egypt once which reminded me of sparrow! Their poo makes great compost for the garden and they are well suited to a small confined space. An adult pair of pigeons will raise around 14 squabs a year.
If you choose to keep pigeons in an aviary you will need to provide grain, grit and clean drinking water, which they will use for bathing in as well. Spread sawdust or bark mulch on the floor of the aviary and clean floor regularly.
A less time consuming way of keeping pigeons is to have some sort of loft or roost. Keep the pigeons in some sort of cage in this loft for three weeks, then they can be let out and will remain in the area. Kept like this there is little expense, apart from throwing a little grain each day, and no work to do in their upkeep.
When air travel gets too expensive you will always have a means to communicate with distant friends.