Any body have a pic of a candled egg on day 18?
Part of it depends on how good your candler is, how good your eyes are, and how clear the shell itself is. A white shell is pretty easy to see inside. The darker brown or colored, the harder. In general after 18 days all you will see is a solid mass except for the well-defined air cell. The chick is filling the rest. You might or might not see movement.
I can still see veins and some light through most of my abandoned eggs. Does this mean there are still a few days left until lockdown?
Not knowing how long they have been incubated I can’t say. You need to pay attention to what you are seeing in each egg, then candle them in a few days to see if there is any development. They may be fairly early in the process. They may have died at an early stage. Some people can see heartbeats or other movement fairly early, but that depends on the things I mentioned above. If you see movement, they are still alive but I have darker eggs. Especially my green eggs are hard to see inside. I usually can’t see any movement in them. If you can see veins and through them, they are not near ready to hatch.
Can someone tell me what goes wrong if you mess with an egg during lockdown/hatch?
Just like Blucoondawg said, cooling off a bit is not that big a deal. During incubation a hen will often leave her nest for an hour or more in warm weather, less time in cold weather. The eggs cooling off a bit doesn’t hurt them. By the time they are ready for lockdown, the chicks are generating a lot of heat on their own. In the big commercial operations where they have incubators that might hold 60,000 or even 120,000 eggs each, heating the eggs late in incubation is not usually the problem. Getting rid of excess heat often is.
Of course you don’t want to get silly about this. If a chick has hatched and is still wet, you don’t want to expose it to a breeze or cool temperatures. Your incubator should not be where an AC vent is blowing on it anyway, so opening the incubator for a short time should not be a problem as far as cooling a wet chick, just don’t overdo it.
I don’t think it is a real high risk based on my incubator and when and how I do it, but it is certainly possible you can shrink-wrap the chick after it has pipped. Different incubators in different conditions pose different risks.
I find the more I mess with an incubator during hatch or a broody hen during hatch, the more likely I am to cause a problem. The more I keep my hands off and just leave them alone, the less likely I am to cause a problem. Some people mess with incubators and broody hens a lot and things normally don’t go wrong, but I find it a good practice to not mess with them because it is possible you can cause a problem.