I'm so sorry to hear about your hen.I just lost a pullet to a chunk of styrofoam. The necroscopy revealed a chunk of styrofoam 1x.5 inches stuck in her crop, it basically caused her to starve despite the fact that she had been tube fed for the past week. It is amazing that she was able to swallow it but she did and it killed her.
That's a sizeable piece...wow.

