Help! My chickens ate polyurethane pipe insulation!!! Could that be causing the crop problems?

[Wannabechiklady]

Hi, all you chicken experts. Since I'm new to this, I was hoping on getting some advice specific to my situation. I have a Wyandotte that has had a swollen/slow crop for almost two weeks. I have tried:

isolating her with soaked food with oil for one day
isolating her with no food
ACV in the water
probiotics/minerals/vitamins in the water
giving her Dulcolax
giving her miconazole
vomiting her (tried once and wasn't very successful, but it worried me)
garlic
colloidal silver
oregano leaves

Now another of my hens, an Astrolorp, started up with it yesterday. I love my chickens, and I don't have vets in the area that take chickens. Does anyone have any suggestions?

Thank you in advance. I'm especially worried about the Wyandotte. Her neck even looks strange today.

Lisa

Update:
My husband just found that they have been eating polyurethane pipe insulation off the well pump pipes! Is there ANYTHING I can do to help them?!!!!