What's Happening With the Hens and Eggs

Well Little Ace has been sitting on eggs now for 25 days.  Since she can not count, she will sit there until the last one hatches or I give up and throw it away.  She started on April 15 with 9 eggs.  Someone pecked holes in 2 of them.  One chick hatched on day 21 as it should, but the little chick got out of the coop and into the run and died.  I have checked in the coop for peeping chicks at least 3 times a day.  Today, just before dark I checked on them and found that Cracker and Little Ace are both sitting on the eggs.  I bet this is very rare.  Brooding hens are very protective and usually won't let any one-human or fowl near her nest.  But Cracker has been sitting on the eggs when Little Ace goes for a little walk.  I had to run and get my camera when I saw Cracker in the nest with Little Ace.  Surely tomorrow we will have a couple of chicks.