Welcome to BYC! I am also your neighbor, so to speak, in West Sacramento! (I moved here just about 2 years ago...) I'm a new chicken mom, built the tractor/coop myself, and have 8 pullets (pray they are all pullets!) in the bathroom in the brooder right now.
They're all different breeds AND ages, due to my insane need to replenish my flock every week or so as Bad Things Happened. Started with four on Oct. 1, one died after 8 days (a light Brahma). I bought four more. One of those died (a Black Sex-link). I started taking them outside for little visits to the coop and run, and my elderly dachshund surprised the heck out of me by dashing by me to catch and kill the oldest pullet at the Top of the Pecking Order - an Ameraucana. About a week later, he did it again, catching and killing the next oldest, a RIR and suspected cockerel. (I am SO much more careful when getting the chickens into the coop, now!!! If he manages to get another chicken, he's going to go live with my best friend..... and that's really a tough decision on my part.)
Anyway, I spent a ton of time in the bathroom just enjoying the chicks. And when I gather them up one at a time and transport them outside for a couple of hours ever day or so to get used to their coop run, I just love watching them interact. This coming weekend, the current oldest - Plymouth Rock Barred - turns 8 wks old. The next oldest will be 7 wks - an Australorp. Then there are two 6 wk old chicks: SLW and Buff Orpington. Two four week old chicks: Ameraucana, and Black Sex-Link. And the last two, 3 wks old: Brown Leghorn and Cuckoo Maran.
Rebecca the Plymouth Rock is fully feathered and ready for the coop, but she'd be alone...... Matilda the Australorp is dang near fully feathered, so I could put them out there together whilst the rest of the flock spend their nights in the brooder for another few weeks...
I don't really know what to do about this age difference thing, now that I've succumbed to the Chicken Addiction in buying 'em like this. At least 8 are the absolute maxiumum number, so I won't keep doing it......
Enjoy the forum and post often - I need more "neighbors" to talk to about my chickens!!!!