So I had found some hen of the woods all over by my house although, 90% of them were covered in white mold or sogged wet and nasty. I found 3 that were good but my mom tasted one after cleaning and boiling them in salted water for 12 minutes and said they tasted metallic. They are definitely hens but I wondered if there were some mold on part of the mushroom if that could be the cause of the bad flavor. 

http://www.flickr.com/photos/63674816@N07/6331866717/in/photostream http://www.flickr.com/photos/63674816@N07/6331869447/in/photostream

there are a couple photos to help.

Those are definitely hens.  It's a bit late in the season for them at this point, so not sure if it's just a natural breakdown thing.

Not sure any mold would have caused a metallic taste, but not 100% either.  Three other possible causes come to mind...

1.  What type of pot did you use to boil the mushrooms?  Some metal (in the pot) may have reacted to give the hens an off flavor.

2.  Did you use regular table (Iodized) salt or kosher/sea salt.  Iodine has a very distinct "metal" bitter taste and the salt may have given them an off taste if you used regular iodized salt.

3.  Did you use filtered or bottled water to boil.  Many municipalities use chlorine and other chemicals to treat the water and some water is hard/soft or in some other way minerally/metallic right from the tap and may have come into play.

Keep the sites where you found them in mind for next year.  You should get some to come back and can harvest them earlier to prevent to mushy/moldy problem.