For the first time ever, I've had several of my own birds' chicks pip on the small end of the shell. In fact, I just had one do it that is not in the same bator nor from my own birds, so we went looking for answers and I think I've found it. In my case, my hygrometer has become inaccurate and my humidity was higher than I realized by a little bit. I found an article in Winged Wisdom magazine about cockatiels, that explained it very well. Thought I would share this part with you all. Again, accurate instruments are the problem-mine had been accurate for many hatches and now, I believe it will have to be replaced. Retest your hygrometer from time to time, even if it's previously been accuratate! Here is the small section for you to read, from this article: http://www.birdsnways.com/wisdom/ww61e.htm Once incubation is complete and the chick is starting to hatch there is now a greater need for a higher humidity level. The higher humidity will make it less likely for the chick to stick to the membrane of the egg. Since the incubation of the eggs is complete, there is no need to worry about the transpiration of water from the egg because at this time the chick has pipped in the air cell and is breathing oxygen on its own. Overly dry membranes will cause a chick to have problems with hatching. Malpositioned embryos will have problems with their heads not in the right position to externally pip the egg. When the humidity has been too high the air cell is very small and the chick's internal pip will often be below the air cell. The chick's need for oxygen is critical at this point and because the internal pip is not into the air cell the chick becomes disoriented in the egg and turns so it is malpositioned and its head is in the narrow part of the egg away from the all important air cell. This results in a chick who dies while trying to complete the hatch. I didn't lose any of these because they were able to put a breathing hole in the shell, but it could have turned out differently. Obviously, during the main part of incubation, it's better to keep humidity on the low side. I try to keep mine no higher than 50%, but my hygrometer being off probably means it was closer to 60% for way too much of the time.