i have a pair of tumblers like that laid lots of eggs but none hatch, soon they will aboanden them mabey try again or look to see if the eggs are clear 21 days from second eggs today for me aswell peckedhen i took 1 of the eggs away yesterday and replaced with a crock one cracked it open and nothing was inside just the yoke mabey try with one of yours.
all the best
martin