I am in the process of hatching both Pekin and Rouen eggs. I started on January 9th and had one Pekin hatch out late on day #26; another early on day #27 and another late on day #27. I now have two with signs of breaking out but they have been this way for over 24 hours with little to no progress....still peeping though. Today is day #28. There are several eggs that have dark insides; would that be from being Rouen ducklings or are they eggs that have not developed and are rotting? Do the Rouen's take a little longer to hatch? When I first candled, I marked some with an "X" that did not show the spidery development but continued to turn them and care for them as though they were viable. Of the 5 marked that way, 3 of them have gone on to be almost filled with dark matter and I don't know if it is a duckling of dark color or a rotting interior. I guess my question is: is there an interior difference in color between Pekin and Rouen eggs when developing? How long should I wait before deciding they are finished and should be discarded? I would absolutely hate to discard a developing baby. Sorry for all the questions; this is the first time hatching for me and I don't want to do anything stupid to endanger these potential babies. Any advice?