If you had the time and room you could also teach them a little about genetics with chickens. BBS and sex-link are pretty simple genetics to learn with chickens. Just remember you pay for quality, when I started hatching as a young teenager I would go around and buy up mostly barnyard mutt eggs (1 of the farms I bought from had a "pure" (hatchery) flock of white rocks) for $1/doz. then I would resell the chicks , at 4-6 weeks old, to whoever I could find for $2ea. I thought it was a fun and profitable hobby at that age, and I did it for a couple years without ever having an adult chicken. You will pay a little most depending on breed/s of chickens and quality of lines and sometimes eggs can be hard to find if you are picky. With chicks you have a little more choice.
Just wanted to let everyone know I may be scarce for a while, I'm switching apartments over the next couple days and the Internet guy can't come out to switch our service for another week, shortly after that I might have to disconnect my internet for upto a couple months until our financial situation stablizes again.