Liz Pevytoe

those look like black soldier fly larvae. They are not worms they are fly maggots/larvae.

You can do this several ways:
1. you can move the finished tray to the top position and leave the lid off for a few days, the worms will move down away from light and the drying bedding.
2. You can put the finished castings in a bucket and top feed and wrangle up all the stragglers that way.
3. You can harvest them (here is a video on worm harvesting: http://youtu.be/OgliNESi8jA)
4. you can use them worms and all, it wont matter much.

Hope this helps. And fyi, in my experience, using a tiered system, the worms tend to stay small and not multiply too much, due it being a small space. Worms need room to grow and breed, they self regulate when the space is small. I know the manufacturers say otherwise but I just have not seen it myself and I have had a working worm factory for demonstration in my classes for 8 years. I use water troughs for my breeding bins.

we had good results with boric acid.

It is my opinion that summer is far more dangerous than winter.
As long as your bin has a food supply in winter, the worms will survive.

A few questions:
1. What is the PH?
2. What are the bin temperatures?
3. How often are you stirring up the bin?
4. Are you feeding anything but the rabbit droppings?

Ants in a worm bin are usually a sign that the bin is too dry. I would suggest soaking it really good for a few days and the ants will leave. At least that is what has worked best for me over the last 8 years.
I have not witnessed ants to be predatory.
If your worms are gone, they likely died or ran away from home if the bin conditions were bad.