Worm Bin Problems: Plastic vs Wood and "Friends with tails."

I am sold on vermicomposting and I would like to make alot of it. I have 3 different kinds all plastic, I have the worm tower, the square bins, and the worm tumbler that I bought for dog poop vermicomposting, but I went to a in-ground system instead. They are all plastic and in the shade but it appears my worms took a beating in the heat this summer. I am trying to make them more productive and keep them going during the winter. I am thinking of getting or making a wooden worm bin because it seems the worms like the wood bins better. What do you think....the plastic WBs seem to fluctuate so much in temperature and worms become very inactive in the winter. Also we discovered we had "friends with tails" visiting the worm bins. Friends tell me their wood worm bins seem to breathe better and offer better protection. The heavy lids make it difficult for rats and raccoons to get into them.

Your thoughts?
Thank you
Sunny

I made my own worm bin out of cedar 2 x 6's and 4x's, and it's on it's second summer, and doing great. I use straw to insulate with, keeping it damp in the summer so it works on the same principle as a swamp cooler. My worms are thriving, so wood gets my vote!

i havent had any problems with my wood bin so far. its nice because you can put a latch on there to keep unwanted critters out. sunny - i see u r in zone 8, are you vermicomposting outside year round there?