Do chickens destroy eachother's eggs?

[dreamdoc]

For the last two days I have found a broken egg in the laying box. One had only the yolk with no shell. Today the shell was smashed but the egg was still inside. These broken eggs are from two different hens. Animals do not have access to the coop or hen house so I'm baffled. Any ideas?

 

[gamebirdsonly]

sometimes when the hens get in and out of the nesting boxes they will break a egg once in awhile and if egg shells are thin then it could happen more often.