I made some homemade chicken stock for the first time the other day. I used chicken feet from pasture-raised chickens that I had to peel some remaining yellow skin off of, and I also cut off the hard-to-remove callouses on the pads of the feet. I blanched them quickly, cut off the claws, and threw them in my slow cooker with some onions, a little salt, a tablespoon of vinegar, and a carrot and let them go on "low" for 18 hours. I strained the broth, and let it boil rapidly for a little bit to reduce it a little bit more and get any remaining fat and impurities that might have gotten through the strainer.
I noticed that there was a bit of an "off" smell when it was boiling. It wasn't bad, offensive, or repulsive, but more of a really subtle smell, such as when butter is left out on the counter for a while and picks up some "off" flavors.
I froze my stock in ice-cube trays, but now I'm wondering...is it safe to eat? Or should I start over?