It really depends on the color of the shells how soon you can see something. White/cream shells can reveal development at 2-4 days. Light to medium brown shells take 5-10 days. Chocolate, blue, green or olive may never reveal anything more than a darkening mass or a more defined air cell. I never toss anything before 10 days, usually closer to 18 for dark or colored eggs. If there is any doubt at all it goes into lockdown.'m sure it's been posted somewhere but exactly how long after setting eggs do they start to vein. I have 3 out of 11 that have been in the bator over a week and have wonderful veins and some movement. The other 8 have absolutely nothing. Are they not viable? Thanks. Sue