Pigeon hatch

[digger]

Need a hint from someone with more experience than myself'. Been raising pigeons for about 6 years and have aloft of about 45 homers. Problem is I've had 12 or so eggs this spring that start to hatch, about a 1/4 to 3/8" hole in shell, then it stops and I have a fully developed chick inside dead. What's up? Too hard a shell? Need a feed change? I use the red grit and oyster shell. Help!

[BMURPH]

I had a similar problem. Switched to a medicated feed and it took care of it. Here is a resource that might be helpful.
http://www.chevita.com/en/pigeons/symptoms/index.php