Well I have 5 in the bator right now and candled them today on day 4..I use a very,very bright light for the source but its still hard to see much. Im pretty sure I can just make out veins starting to form. I can see what looks like the start of good air pockets. Im pretty sure 4 are fertile, one is pourous looking. Im thinking its not fertile. Ive always heard that an air pocket forming is a good sign? When do you usually candle your brown eggs for a definite answer?