Assisting the hatching of a cockatiel

[Master Chief]

This is the second time my cockatiels lay eggs. The first time they weren't successful. Now they laid 4 eggs one has already hatched the 2nd one we noticed that it had pipped somewhere around 8 and it was almost out. We come out the next day to check on it and it was still in its egg, so we grabbed it out of the nest to check in on it and it unfortunately passed away. We still don't know why it died. While we saw it was in it's egg still I saw that the 3rd egg had begun to hatch so we waited an good 2 hours to go and check up on it and since it still hasn't hatched we went in helped speed the process to about half way. Somewhere along the way I nicked a small vein. The chick is still in it's egg and we put it back in the nest. Was this the right move? And do any of you know what might have happened to the 2nd egg?

 

[MGG]

This is the second time my cockatiels lay eggs. The first time they weren't successful. Now they laid 4 eggs one has already hatched the 2nd one we noticed that it had pipped somewhere around 8 and it was almost out. We come out the next day to check on it and it was still in its egg, so we grabbed it out of the nest to check in on it and it unfortunately passed away. We still don't know why it died. While we saw it was in it's egg still I saw that the 3rd egg had begun to hatch so we waited an good 2 hours to go and check up on it and since it still hasn't hatched we went in helped speed the process to about half way. Somewhere along the way I nicked a small vein. The chick is still in it's egg and we put it back in the nest. Was this the right move? And do any of you know what might have happened to the 2nd egg?

Welcome to BYC! Had the second egg started to zip? If they start to zip and get stuck they'll die within twenty minutes or so. They get worn out and can die very quickly from exhaustion. I just had that happen with a duck egg the other day, he was almost all the way unzipped but I missed it and he got stuck and died. If you are there and notice they have stalled out, you can help them out and they'll be fine.
How much did your egg bleed? You can put some cornstarch on a q-tip and dab it on the vein gently if it's still bleeding.
If you hit a vein it wasn't ready so I'd say that was not the right move. I usually candle prior to assisting and if you candle the pointy end, there will be a small gap holding any remaining yolk and veins. In lighter eggs it's really easy to spot. If you see any veins in that area don't assist. Cockatiel eggs are white so definitely light enough to check on.