In the background of the photo is the candler we use to determine fertility in African penguin eggs. We use this unit in a dark room and place an egg in front of the beam of light. By between Day 6 and Day 10 of incubation (African penguin eggs take 37-38 days to hatch) we can tell if the egg is fertile. If fertile, there are blood vessels that can be seen through the egg shell. It is important to determine fertility early on in development as it allows us to plan for eventual hatching and chick rearing. In addition, it lets the staff know about the incubation abilities of the couples. We keep records on each egg and those records are also kept in each of the parents records.-Pamela Schaller