Will packing peanut cause impacted crop?

[washingtonannie]

One of our hens dug up a packing peanut that was buried in the back yard. I tried to get it from her, but she swallowed it. Do I need to be worried about this? If so, how do I get the hen to vomit it out? I'd appreciate any help.

 

[TM Chickens]

Our hens have ate several packing peanuts before we could stop them, with no visible ill effects.