smelly incubator!

My 3rd batch of eggs have started to pip on day 20 (well 1 has) but there is a very strong smell in the incubator! Im sure all the eggs were still growing away but now im worrying that 1 is bad and gonna pop! or is this smell just normal and I didnt notice it last time?
And if 1 has gone bad how am i gonna get it out without dropping humidity and stopping the others from hatching?? 

Debbie

Try candling the eggs to see if they all have chicks or not.

I thought that but am worried the humidity will drop too much!? especially as 1 has pipped!

personally i would take the risk, if you smell each egg quickly you should be able to find the offending one, if you leave it it could compromise the rest of the hatch.

There's a relief 
Terrific thunderstorm here tonight tripped out the power and the incy started flashing "P".
Thought I remembered reading about resetting it but still had to wade through the manual to find it! Meanwhile the ex-batts gave me the run around trying to get them undercover, silly things