I've been keeping chickens for a couple of years and have successfuly dealt with this problem in the past. One of my chickens passed away today and upon finding her it felt like she had a baseball stuck in her. I did an at home necropsy and found a normal size egg covered by a hard rubbery stuff that looked similar to fat. This was at least a 1/4" thick and it was impacted to the uterine wall. Any ideas to what happened? Thanks in adbance.