I started out deciding that I'd get 3. 3 would be the "perfect number". Apparently, other people wanted the same breeds. When Dunlap opened the first day they had buff orpingtons, I stood in the hatchery waiting for my buffs for almost an hour, that is, before they sold out of the 3,000 6 hour old chicks they hatched. So I ended up buying 5 Easter Eggers. Totally makes sense. I went back two days later, and got 2 barred rocks and a black sex link to replace the one EE that died. Ahhh, chicken math. Suddenly that 6 chicken coop doesn't work. So we made another coop for 10 hens. Then, of course, I ended up getting 2 BO hens, since I didn't get any to begin with. Right? Then I traded my quail for 3 Australorp hens. Then I found a serama hen at a shelter, and I somehow managed to integrate the little brat into the flock. The the school was re-homing chicks they hatched, and I took the hurt one. I had to get her a buddy, so I went and picked up a chick from Dunlap's last BO hatch. Then the hurt one died. Then of COURSE I needed to get another, so I go back and they have the first ever Silver link hatch from the hatchery. Now I need a new coop, and I won't be able to build one till the end of June. Luckily the pullets are still small.
In short, chicken math will go from 3 BO pullets to 2 BO hens, 1 BO pullet, 3 Australorp hens, 4 EE pullets, A Black Sex Link pullet, a Silver Sex Link pullet, A BR pullet, a BR rooster, and a Serama hen.