Oh, I loooove chooks. Always good to have a couple about. They are stoopid, but lovely. And they actually would make great house pets, if they could be house trained. Bantam ones that is.
We always seem to have them (althought not for the last 2 years. Hmmmm, once we're done renting

) And I don't want to rain on your parade, but there is no way you would be able to make any kind of profit on selling eggs/chicks etc.
Because hens are so easy and cheap to keep, plus a good layer will lay one egg a day every day for years, there is zero demand for it. To make anything, you'd have to be a chicken farmer, working with hundreds to thousands of birds. You would even have trouble giving away the eggs if you had, say even, 4 good layers.
However, the up side is, because they are so easy and cheap to keep, you don't have to sell any chook by-products

Once you have a coup for them to roost in, you're set. A hen dosen't eat more than maybe 30-40c of feed a day, and if you're yard is fenced, they will keep the bugs low in all your gardens and you're plants wil be happy.
Oh, and don't even bother with a rooster. They are, generally speaking, aggressive, loud and they will fertalize your eggs and you will have chicks. Chicks are hard to get rid of - so just buy 2/3 few day old chicks, if you want to experience that. When they grow up, it's out into the yard, and you have friendly, happy hens.
Good luck, and sorry about the rant
