I can't answer your question James, but the pictures of the incubator jogged my memory. A few years ago a cheap self-turning incubator came onto the market and many were bought. At the first hatch reports said that entire batches were stuck in the shells and the reason for this was the turned angle was far too small- it should be at least 90 degrees in total. I have a memory that the angle was only 45 degrees in total, so check that and if it is too small I advise transferring your eggs to another incubator, or turning them manually (mark each egg) or stopping the hatch.