If you have feral chickens running around, it's possible something happened to momma and the little ones were fending for themselves, although it does seem a bit too much of a coindence that they would wind up at your place. Then again, there are no coindences! Do you happen to live in Fair Oaks? I know they have quite the feral chicken population (I almost did a drive-by rooster drop off last year, but then found him a home!). Good luck with those little cuties!
Liz
Liz