Listen day 31 is a lot.you either follow above mentioned steps or you might lose them.Some of your eggs are zipped so just help them out.For others, follow my steps
1)STEP1: candle the eggs ok and see if you see the chicks beak at the air cell.If so that means they have internally pipped
2)STEP2:If step 1 is good then make an external hole at top of air sac.Make sure that chicks beak is visible and not covered by external shell.This will help hi breathe...