Found: Fantasy novel about animals carrying cursed gemstones

This would have been a fantasy novel written in the 1970s or 80s because I read it in the 80s, about a number of animals and I think also a boy, each of them carrying some kind of gemstone implanted in their bodies. I know there was a toad who had his gem in his forehead, and it caused him migraines. I know somebody had a gem in a limb or shoulder or something and was lame as a result. All these characters came together to figure out what to do about these crippling/cursed gems, and that's about where my memory gives out. I think there may have been a witch involved.

The Unlikely Ones by Mary Brown. The human is a girl, who has been told she's ugly. https://www.fantasticfiction.com/b/mary-brown/unlikely-ones.htm

>2 sueelleker: Touchstone: Unlikely Ones

>3 RosetheReader: Yeeees! Thank you! That does look like the one!

Just added it to the Frequently Sought list, since this seems to be the 4th time people have come looking for it.