You will get different opinions on leaving the egg versus taking it out. I live in Southeast Texas so it gets very hot. During the early season when temperatures are moderate, I leave the eggs. If a brood is in July heat, I remove the egg about 4 days after the others have hatched.

Linda C

I'd wait at least another day, but when did the first egg hatch? Our first brood of 4 last year hatched over a 3 day period. 2 hatched on the 24th of the month, 1 on the 25th and the last was found to be hatched when we looked in on the 26th...

One other thought.... I believe if there's something wrong with the egg Mama will either bury it in the nest or remove it.... so I'd leave it alone.

Thank you all,the others hatched yesterday.I will check again tomorrow....Jane

I would rather be safe then sorry and wait several more days, just in case.
Tammy

I have had them hatch two or three days later.

If it were to hatch 3 days later, the chick would be so far behind the others, it would not likely be able to compete for food, etc. Those babies grow so fast! If you want to remove the egg, it must be done very carefully. To break the egg accidentally in the nest would be a very bad thing. You could lift it out with a spoon; safer than clumsy fingers.
BlueBars

I checked the box when I came home today and the unhatched egg was still there.I removed it with a spoon as suggested,it was definately not fertile,so I am glad I did remove it before it became a problem.I agree if it hatched too much later than the others,it would be fighting for food.However that was not the case,so all is well and there are 4 beautiful babies in the box.Now to decide how long to leave the wren guard on.Decisions,decisions.Who said this wasn't work?But it sure is enjoyable.Happy bluebirding to all.......Jane