Temperature spike on day 22 of incubating chicken eggs?

[Farmer Viola]

Update: After the temperature spiked on day 22, for some reason my temperature was completely off the last 3-4 days. I finally called it quits on day 26 and removed the remainder of my eggs. I do believe opening the eggs to determine what went wrong would yield valuable insight, but seeing as I'm mostly positive it was the temperature, I don't think I could bear to open the eggs and see the poor little deceased chicks. I guess I'll just have to chalk this up to a lesson learned and experience gained.
I appreciate everyone's advice/suggestions and I will keep those all in mind the next time I incubate eggs, which will be once I've updated my equipment. Good luck in all your endeavors!

sorry to hear that..

I will be looking forward to your next incubation project! onward and upward!