Another crockpot error I accidentally set my crockpot, with raw chicken and broth, on warm for a little less than one hour. I read answers to a similar question, but since this is chicken and only for 1 hour, I thought I'd ask if it's likely okay or not.
If we go with the 2 hour rule, then you have about an hour to get it back up to a safe temperature.

So either turn the crockpot on high 'til you get it back over 140°F, or remove some of the broth and use another method to heat it and then re-combine the two.