I was going to buy worms and talked to many suppliers. I was concerned about an environmental impact if they escaped because the best ones were not native to America. One of the suppliers informed me it was to late for many have escaped others. I then made a decision, I can attract them then, and that is what I did. I made a new compost pile 6 foot square, 5 foot tall. I dug a hole in the bottom of it 4 foot square, by 2 foot deep and in it I put the most desirable eats for the worms in the hole. I added horse manure mixed with straw, coffee grounds, egg shells crushed, fine sand, all the rotted vegetables, fruit, moldy bread, uncooked oatmeal, basically everything you find in a normal compost pile. Then a big pile of leaves to shade it and keep it from drying out and getting heated by the sun and air. After four weeks, I moved the leaves and discovered I had been invaded by several species of worms that like this type of eats. There was none of the normal type earthworms in the pile but all were either red wigglers, European night crawlers, or another type of what are called composting worms. Before long they had multiplied so much I was able to take them to other compost piles I had and now they are in all my planting beds too that I keep heavily mulched. I now have trouble keeping my beds mulched and my pathways between my garden beds mulched, because they process everything that is decomposing. They do not hurt my healthy living plants but sure make them grow better.
As for as not adding certain things to your compost piles, such as meat, dairy, orange peels, and etc. do not believe it. If your pile is healthy and big, it will consume it. If you really want to know more about composting, read "The Human Manure Handbook" by Joseph Jenkins. You will be amazed at what compost can do for the earth and it is a free download.