Your worms should arrive in bedding, which you should put all into your bin. I am guessing that the horse manure has not heated up your bin, and that should be food source enough. How many worms? I always add a good 3" layer of damp shredded paper on top of the food. Depending on what kind of bin you will be putting your new friends in, and how far/long they have traveled, you may want to leave a light on over the bin for the first few days until they settle in. Have fun!

Worms arrived safely yesterday. We just put them on top of what I had there and they worked their way in very quickly.
When my husband came home he decided they needed more on top so he made a divider for the bin and we moved all the bedding to one side. The worms had already worked to the far side of the bed :-) I put some coffee grounds in there with them and now plan on just leaving them alone for a week or so before adding anymore food stuff.

Another question: Should we leave them TOTALLY alone or is it ok for my son to go and look at them once or twice a day?
We have a bin 18"high 4'wide and 2' long, wooden with a lid and he stapled a screen in the bottom because there are air hole down there and he thought they would try and escape out the holes. I ordered 1 lb. for worms. So now the bin is 2' wide with the divider in place.

My worms are so used to me looking in on them that they hardly care about the light! ("Oh......It's her again"!) Looking in , not digging in, I don't think is a problem. Have fun.