Not to be discoraging but if you are buying new lumber then likely you will be loosing money.
If two good hens can lay a dozen eggs a week thats only a couple bucks and you need to feed the hens so really each hen might only make/save 50 cents a week at the most. Hens likely only will lay eggs...
If you can find/build very low cost housing it can likely save money, otherwise they will likely be a money pit. None the less fun and possibly entertainment... better value than a pet dog or cat.
Very easy to drop hundreds of dollars in coups and it would take years to pay back at a couple...