Well, they should of bolted in the spring. All I can think is if the plants were planted too late last fall and were tiny in the spring. If a plant isn't mature enough in the spring, it won't bolt. I can't imagine it would do it this fall, but I don't know for sure. You may have to wait until next spring.
Remy

I doubt the plants were too small. I planted them in September, which is the recommended planting time for fall crops in my area, and with our mild winters they had all winter to grow and got pretty big.

The only odd thing is that the seed was pretty old, from 2006, and had been kept in bad conditions (in my mom's garage). Since they germinated fine anyway I thought they would be ok, but is it possible they could have been damaged? Not to the point where they couldn't germinate, but for some reason their "biological clocks" were messed up? (I'm not sure how that works.)

Since it's not like Fordhook is a rare variety or anything, I wonder if I should just yank them out, if this behavior is not normal for chard.