chickens pecking fake eggs-help!

[splady]

We have one broody hen sitting on a big clutch of fertilised eggs in one of the nesting boxes.
In another nesting box we put all the polystyrene eggs (which we were using to show the hens where to lay).
Today we found the polystyrene eggs pecked to peices.
I'm worried that whoever pecked the eggs might turn on the fertilised eggs!
What should i do?!

We have 3 laying hens, one broody hen, one teenage hen (due to lay any day!) and one young cockrel.

 

[Nonny]

Can you swap the polystyrene eggs for plastic ones or golf balls? I'd be worried about the girls ingesting polystyrene bits.

 

[splady]

We've taken the polystyrene eggs out of the nesting boxes to hopefully stop them pecking.
I wondered if the broody hen had found the other polystyrene clutch and pecked it out of jelousy?