New to keeping chickens, when my aracuna/ new hampshire cross hens went clucky I went with the flow, left them in laying boxes, together, in contact with the other chickens, added eggs after they were sitting, etc, lots of novice not best practice activities... anyway, I did eventually start looking things up on the internet and marked the eggs and made an estimate of the starting dates. I do know that all eggs were marked prior to xmas. My first three chicks hatched on the 9th Jan and each couple of days came another 1 or 2 chicks over a week, then nothing for 3/4 days. I knew that it was now well over 21 days, but being a hopeless romantic, I waited. After all, the hens hadn't abandoned the eggs. So glad I did! Beyond all possibility, on 21 Jan another egg hatched! A real cutie. With the hens still sitting and some remaining eggs looking and feeling heavy, I'll leave it to the hens to know best.