Over the summer the retail price of eggs has increased anywhere from 20 to 50 percent, which is a significant change for consumers but also for people who are pushing Abenomics and its focus on reigniting inflation, since eggs have for years been seemingly been impervious to price changes. At the beginning of May, it cost about the same to buy a package of 10 eggs as it cost to buy a package of ten eggs thirty years ago. As the prime buka no yutosei (best "student" among product prices), it's one of those constants people took for granted.
However, the sudden increase was not entirely due to serendipity or natural market forces. In fact, the price hike was engineered in a bid to maintain market stability. In 2011 the agriculture ministry implemented a subsidy to control the price of eggs. Because a sudden drop in price can have an immediate harmful effect on egg producers' bottom lines and potentially damage the industry as a whole, the ministry automatically provides funds when the wholesale price goes below ¥159 per kilogram. These funds are used to cull egg-laying chickens in order to reduce supply and put pressure on demand, thus pushing the price back up.
According to Tokyo Shimbun, in May the price dropped below the designated line and the subsidy kicked in. Producers receive ¥150-¥200 for every chicken they kill, and the ministry estimates that from mid-May until mid-July, when the subsidy was available, about 5 million birds were culled. Not all were thrown away. Many were processed and sold as meat, for which the producers can earn an additional ¥20-¥50 per bird, an aspect that makes the system even more popular among producers since it rationalizes the process of replacing chickens.