I know this thread was from 09 but I thought I'd add my experience in case anyone searched for do it yourself fixing of an egg bound , broken shell inside hen . This has worked for me numerous times and has saved the lives of many hens over the years and I can say " knock on wood , I have never lost a hen to an egg issue ." If you notice a hen who is oozing yolk or egg white from her vent .
A. Remove her from coop immediately, this must be treated right away to prevent infection .
B. Get some extra virgin olive oil and fill the sink with warm water .
C. Wash the outside of the vent with warm water only , no soap . Pour olive oil on vent opening and on middle finger .
D. Slowly insert middle finger into vent as much as it will allow and feel around for shell, if you feel soft shell , use finger to scoop it out but if you feel hard shell you will have to bring her to a vet for removal . Once you have removed all the pieces of shell , use a baby snot remover to irrigate inside the vent , then dry the outside and put a little more olive oil on the opening . Put this hen in a carrier and give her water with antibiotics in it for five days . You can buy the powder from tractor supply for seven bucks . It's called oxytetracycline , broad spectrum. I always keep it handy for bumblefoot or anything else that might arise .