Every animal on our farm has a "job" to do, or they don't live here. Cows give us steaks and hamburger. Goats keep weeds under control. Pigs till and fertilize a garden space, and give us bacon and pork chops. Dogs keep predators away, bark like hell when something's wrong in one of the animal pens, and alert us when visitors arrive. Cats keep the mice at bay and us entertained. Everybody pays their room-and-board.
The chickens give us eggs, of course, as well as fried chicken and barbeque. We raise all of our own - no particular breeds anymore, they're all mutts. And that's fine. We started with a variety of dual-purpose breeds, and it's gone from there. We let the pullets become hens, and the cockerels become dinner. Hens give us eggs, and roosters provide security and fertile eggs for hatching. Occasionally, someone gives us a bunch of rescue chickens, so that keeps inbreeding at a minimum. No foo-foo fancy delicate breeds, here. They work, or they get eaten.
I also enjoy studying chicken genetics and breeding them is the ultimate demonstration of how those genetics function, so I guess pets to breeders was a natural progression for me. I do still consider them pets, although that complicates things a bit because when they're too old to produce healthy offspring the individuals will have to be replaced in the interest of progressing with preserving them. 
I still have my big, mixed flock of random breeds for fun, though.
but now that I have them it's because they are so cool, photogenic, loving its been come more then just eggs. I don't have pure breed I have mutts and that's OK.
