Ok, I have a gram scale lined up. I am going to stop and buy it after work today, and set 41 eggs tomorrow morning. The eggs my hens lay are a darker brown, almost impossible to candle to judge air cell growth. My plan is to weigh the eggs. The eggs should loose app. 15% of their weight during incubation. My question is: is it save to figure about 5% per week, or should there be more or less during the first week then the third week?