Incubation day 29..how long is too long!

I am incubating my eggs, one is not going to make it..it stopped developing almost 2 weeks ago. The other one was doing great...but now it is day 29 and I still have not seen anything happening. I shone a quick flashlight on it and the air pocket seems good, the rest of the egg was pretty much impossible to see through as it was full. My temps have been dropping at night so I am thinking that could delay the hatch a bit. But how long is too long? These are Rouen/Blue Swedish x's.

Thanks!