In that case, I would probably give them another day or two, then candle again to see how they are doing.
Have you read the article on assisted hatching? It talks about when to assist (so you don't cause harm by trying it too early), as well as how to assist...
If you candle the eggs now, do you see any movement or any signs of life?
Since chicken eggs normally hatch at 21 days, and yours are at 26, I think there is a good chance they already died and never will hatch. But if they are still alive, then obviously I am wrong about that.