Over here it's known as 'knitbone' and both humans and animals use it. It contains active ingredients including allantoin which speed up the healing of broken bones and other wounds, whether applied in a poultice/ointment, or steeped, or fed, or whatever. It's sold in shops in little jars too. I've used it reliably for that extra quick healing of broken bones and wounds with animals.... When I can get it to grow. It doesn't like my part of Australia. It's also pretty nutritious and works as a poultice on the inside for damaged gastrointestinal tracts..
There's a fair bit of conflicting advice and as far as I know there are at least two varieties, one of which gets badmouthed a bit. We used the blue/purple flowered one, I don't trust the pink flowered one offhand. Did a quick search and came up with this info:
Two species, S. asperum (prickly comfrey) and S. uplandicum (Russian comfrey) contain very high levels of echimidine, one of the more potent alkaloids. Adding to the problem is the fact that these varieties are sometimes labeled as “common comfrey”.
The one we use and trust is: Comfrey (Symphytum officinale) which is "a perennial plant with broad, hairy leaves and purple flowers."
Which isn't much use without photos I guess but at least you know not all comfreys are to be trusted. The older variety (blue/purple flowered) in my opinion is safe, and that variety has the most literature backing it up over the centuries, but always pays to know your specific herb when your animals are eating it... Best wishes.