Not so simple ? if chicks are still developing

[RedSunshine]

I've recieved some eggs from a neighbor that he gathered around his yard. A few of his hens are kinda randomly broody, sometimes they'll sit on the eggs till hatch(rarely though), sometimes they'll sit for a few days or just hours then abandon. So I'm really uncertain in the history of each egg. I've candled each of them, each in completely different stages. I haven't noticed any veins in any of them, but I'm afraid that could be due to not having a strong enough light. Some eggs are in the early stage also, which could account for the lack of veins.
My main question is, how can I tell if an egg is a keeper or a stinker?
Also, when does the embryo start to move in the egg? Figured I could tell by if it is moving or not?

 

[oldhenlikesdogs]

You should see veins by day 10. I currently see nothing that indicates yours are developing.

 

[MGG]

Egg pics 4 and 6 look viable to me. The other ones, I'm not sure. How long have you had these eggs in your incubator? What is the temp and humidity in there? I would say those eggs look day 4 to me. Get a stronger light though, phone flashlights work pretty good IMO.

 

[rjhsh]

all look bad you can see veins as early as day 3, sometimes hens will sit start the incubation process and then get up, that's when you will see an egg never grown passed a stage is because the embryo stopped at that stage