I've just noticed that the BYC project manager has produced a series of articles on various herbs, including comfrey, https://www.backyardchickens.com/ar...e-to-a-nutritious-and-sustainable-feed.78456/I actually took the camera into the garden to show how much damage the chickens can do to emerging perennials: this is dandelion and comfrey View attachment 3467142
and this is centaurea and primrose
View attachment 3467143
The centaurea in particular takes a battering, but it will overcome it, send up 8' flower spikes, and self seed all over the place. The chickens' foraging actually stops it taking over I think.
I think the first photo shows that we can trust our chickens' instincts to go for the young new shoots and not to eat too much of it, if left to choose for themselves.