I have read several comments on the subject but found no real answers. Are their eggs safe to eat? Will the chickens die? One hen, my Orpington 's comb is pale? Is that due to the foam insulation? I am worried.
Nothing wrong with the eggs. If a chicken ate enough of it, it could cause an impaction. If it was just a little, then it may pass with no issues. Mine ate the foam insulation off a hose riser once, no one had any problems, except me for worrying. But it would be best to remove or cover that insulation so that they can't get to it any more. Anything peck-able is likely to be tried out by them.
If your are worried about them passing the styrofoam you could possible feed some warm oatmeal that has been laced with olive oil. Both will help them empty their crops along with the grit.
You can also check their crops to see if they are overly full or feel mushy. Also check at night then in the AM to make sure they are emptying all right. Pick up the feed at night so they can't eat as soon as they get up and before you have a chance to check them.
Styrofoam is like M&Ms to chickens. I once had juveniles eat an entire foam plate before I realized they just LOVE to eat it. Everyone was fine and even my bantams on occasions will find a piece of insulation and party on.