is this egg pecking?

[lilyblossom]

I have a flock of 5 Buff Orpingtons that I raised as chicks since 4/2. Last night I introduced 2 Rhode Island Reds apx 2 years old. I checked the nesting box this morning and there were no eggs. When I checked this afternoon there was an egg but it was "smashed". Is egg pecking the probable cause? If so, how do I determine who is doing the pecking? Yowza!!