Incubating eggs, are they a failure?

[Eden83_haaretz]

Ok I there were four eggs, the hens was laying on them, then two days ago she sort of abandoned them (another hen started laying eggs there). Then today I thought "I'll take them out, they must have failed" and one of them was hatching, so I took them all out, put them in an incubator, and helped the chick be born (it's strong and healthy, dried out already).
I decided to candle the other eggs; one seems to have something in, but didn't see any movement... The other seemed like they had stuff in but there was runny liquid, so did they fail?

 

[Tonyroo]

It's hard to tell, if you weren't keeping track of the progress, you wouldn't really know if there going to hatch. If it seems to have fluid in it, it's dead.