Piggy only has problems pooping when she gets panicky too. For example if we leave her home in a crate and someone comes in the house but doesn't come down to see her or let her out she will do it. We can't put anything in her crate or she shreds it, we tried everything. For a while I was even buying fleece baby blankets at the dollar store and tossing them if she pooped. We gave up on that after a while. The mess was terrible, so I can relate to hours of cleanup… by the time you get her cleaned up and the crate.
We did some desensitizing and left for short periods like I described before, and that helped a lot. My friend that has a B went to the vet about her anxiety, hers would cry incessantly, and they actually gave her meds, prozac I think, for it. I think she tried it, but didn't think it worked enough to do it. Sounded crazy to me.
It hasn't happened in a while so we have been lucky. She has come to terms with her crate now and will once in a while go hang out in it by choice, so I know she doesn't hate it.
Have you tried one of those snuggle buddy things? I wonder if you could find some way to protect it if Darwin had an accident.
Best of luck and lots of patience!