I was so new to chickens I'm sometimes amazed mine survived. Her air cell was on the diagonal a bit actually, and was just overall not a perfect hatch.
Still a loss though? I would assume so, since I don't see a pip. One of mine last year almost got shrink wrapped, she had pipped but the membrane was drying out. She was the last to hatch under my broody. I noticed, luckily, and was able to moisten the membrane, help her tear it a little, and...
That's a shame.
Could you post a picture of the peachick with the deformed neck? Or have you found it a home already? I'm just interested to see how severe it was considering the malpo was so awkward.