I've already done the Google thing. It was inconclusive. Some people had success, some people did not, one poor guy killed nearly all of his eggs, and in the end it was all simply anectdotal. I did notice a number of "experiments" where someone dowsed the eggs and promised to report back, and then never did. This normally (but does not always) indicate a failed experiment. There were some mentions of Japanese egg dowsers on production lines, but absolutely no facts to back those statements up. In fact, most of them were preceded by, "I've heard that...", or "I've read that...", which is a red flag for horse apples. Facts have citations; horse apples were heard somewhere.
It was implied that this egg dowsing was done on a commercial scale in Japan. I could find no evidence of that, hence my interest in the article. I'm particularly interested in the name of the union being discussed, and what poultry farms the dowsers work for. I can find plenty of information from various poultry concerns in Japan about the wonderful machines that they use, but I've found no mention of dowsers. They may not want to discuss it, so other sources might be required.
I appreciate the link in your later post but it doesn't provide much in the way of information. I accept that there are dowsers in Japan, but what I really want to know about is commercial egg dowsing in Japan.