Are you channeling your best self with this comment? (If you're not sure, check out our Code of Conduct.)
I strongly advised *AGAINST* using such old stock. That's simply too risky in my book. Of course, no one here can give you a definitive answer since there's no way for any of us to test the toxicity of that particular batch of chicken stock, even if it reboiled.
Another factor is flavor. I notice a substantial drop in flavor quality of refrigerated stock after 3-4 days.
In the future, your best course of action would be to refrigerate only the portion of homemade stock that can used in the next 2-3 days, the rest should be frozen. I typically portion these out in plastic pint containers for convenient defrosting.
I've discovered jars of 10 day old stock hidden in the back of my fridge and smelled it and there is absolutely no way on earth I'd put that in a dish.
Anyhow use your best judgment and good luck.