I regularly put comfrey leaves in my bins, especially those for which I have no other waste at the moment. The comfrey is a very fast source of food for them as it rots in just a few days, and comfrey does contain lots of nutrients. Comfrey is particularly useful for bins about to be harvested since I can still feed the worms, but don't need to worry about having all kinds of undigested stuff in the castings at harvest. Generally, for the last month before harvesting a bin I either feed nothing new to the worms, or just a small bit of something like comfrey. For my bins (Rubbermaid 27 gallon tubs), I put in about 2 quarts of comfrey leaves per bin as a feeding.
Renais

Our comfrey plantings were just put in last year so we have not harvested much of it and the little that was went to the hens. The first worms came along shortly after the comfrey and I put 2 or 6 on each one. Later in the summer I saw these worms active in the duff of these plants, they are self muchers so the worms seem to love living with them.

I love comfrey for the way it grows even in our poor soil. After stuffing some crowns into the ground a few weeks later we started getting leaves, soon these were plants that were a couple feet across and we were continually picking larger leaves all summer. You can harvest the entire plant once established and it will be back in a month.

Ours stayed green until temperatures got down below 20F then the plants just died back to the ground. Leaving the last of the leaves for the year lets the plant work on growing its roots and creates a habitat for spiders and other garden goodies to winter over in.

Renais, great idea on using it as a pre harvest food. Comfrey does break down very fast. Only problem I could imagine is heat if too much was put in.

One interesting thing comfrey produces is B12, one of the few terrestrial plants that does that. Just parroting what I have read there but no reason not to believe it.

If you have your chickens in a confined space, then I highly recommend using comfrey as a planting surrounding the space. Plant it so that not all of the plant can be reached by the chickens, but so that much of it can be reached and eaten as it grows. You can take the chicken manure and spread it around the comfrey plants without worry of it burning. I've even grown comfrey in large pots with several inches of chicken manure on top. The beauty of this system is that it processes all of the materials from the coup into more useful feed. Chickens love comfrey, and it has a reasonable amount of protein for them. If the chickens cannot reach enough of the comfrey, then pull off some leaves and toss them in. If you can allow your chickens periodic access to the comfrey, they will do a good job of trimming, and will not kill the plant.

By the way, as an experiment last spring I took a single comfrey plant and broke apart just a few of its roots into very little (1/2-1") pieces. Of the 164 that I started this way, only two did not sprout. One of the ones that sprouted died, all the rest lived and thrived, including a bunch around a chicken coup. Comfrey is very easily multiplied.
Renais

Yes it is quite adapted to reproduce Renais. We had trouble with our first roots we planted out with most of them dying. These were small root sections like you described. We had some leftover in a bag on top of the refrigerator with a moist paper towel from the same batch and all of those sprouted and continued to thrive after transplanting outside. I think part of our problem with the ones that went straight into the ground was that we planted them too deep.

Anyhow, pre sprouting is what I intend to do in the future with small root sections.

We also purchased a good number of crowns. Ours were mostly 1 year though we did get a few 2 and 3 year. The older crowns were loads larger but the first years growth was close to the same from all of them so I would just get the 1 year if getting more crowns or using a nursery bed for propagating more.

The chicken fenceline is one place I planned to plant them also in the runs with wire cages to keep the hens from taking the whole plant down. One of Black Sex Links reduced a fair sized plant to nothing in less than an hour, they do love them. We also chop and offer leaves to them along with other garden goodies when they are in season, other favorites for them are cherry tomatoes and pumpkins/melons. A cantaloupe becomes the thinnest of possible skin, crazy how efficient they can be.

I have read about comfreys love of nitrogen and that it is a rare plant in that chicken manure can be used fresh on it. This is all part of our plan for making the ground better here, chickens, worms, comfrey and now mealworms along with the garden are all hopefully going to work together (housed separately of course) one feeding the next with us taking our cut along the way.

One other thought on feeding comfrey to the vermiherd. It is a compost activator so adding too much to a high carbon worm bed might light too much of a fire. How do you add the 2qts to your bins?

If I get chickens I will follow your instructions and both plant comfrey around the edges of the fence and break them apart and make lots more plants.

I put all of my additions to the Rubbermaid tubs at the very bottom of the tub, and then dump the contents of another tub over them. I've not had a problem with the material overheating, and if it did, since it is at the very outside bottom of the bin, I think the worms would just leave it alone and work material above. Dumping one bin into another serves a couple other purposes: it insures that if there is an anaerobic layer at the bottom that it is now aerated, and it makes sure that the new additions stay moist. It also allows me to check on the state of health of the worms easily since a fair number will be at the very bottom (now top) of the material when dumped.

My bins have only one hole, 1/2" diameter, about 2" up from the bottom on one side. I use no lids. Dumping the contents helps insure that the top materials get moistened periodically.
Renais

That seems like a good plan. I like it a lot.