I defrosted too much chicken stock. Is it safe to re-freeze it?

Bring it to a boil and cool down. It will then be safe to refreeze.

Boulanger,
You are correct.
I missed the "defrosted under refrigeration" part. Oops! Must be getting old.
Sorry.

@declan, as long as the stock hasn't entered the temperature danger zone, of generally of between 40 and 140 degrees F, all is good. And if it has, it needs to be treated as a reheated food, and reheated to 165 degrees, then cooled to 70 degrees within 2 hours, and then to 40 degrees or less within 4 hours.

I think @Randi is there.

ANY organisms.

Can't agree. You need to re-boil it first. Then you have killed off ant micro-organisms.

It sounds as though you treated it exactly as you should, especially thawing under refrigeration rather than at room temperature. Go ahead and refreeze it.

Absolutely. If any doubts, smell it....you'll know. :/