So what is the maximum days before I know the chicks are not alive in the shell?
Do you know for certain that no additional eggs were added under the hen during her sit time?
You can candle the eggs and look for movement, or you can go ahead and toss the eggs now. Generally 23 days is about maximum for chicken eggs, under normal circumstances, but I've seen here folks hatch some at 26 days, but I would be more concerned about weird developmental issues with that much delay.
I don't think anyone could blame you if you call it quits now.
Thank you. It has been quite an experience! I or these chicks could not have made it without the guys on this site helping me through it all.
I'm sure your thread will help others in the future also.