This is great....if I only had a saw....anyway, on the topic of them destroying the herbs, I have two oregano plants, and one each of rosemary, thyme, spearmint, and aloe; IDK what all they eat, but I know they eat the oregano and the aloe, and I think they stay away from the rosemary altogether. Anyway, they hadn't destroyed my plants (there have been up to twelve chickens with access to them since last spring when we got them, and we got them as small plants from Home Depot and/or Lowe's). I hope that helps you out with something. =)
You might plant them in something else until they're large enough or you might try putting some of that lattice over them such that they're growing up through one of the holes, then the hens wouldn't be able to get to the lowest parts of the plants (thus, destroying the plants' ability to recover if it's over-pecked at some point).
I don't know.
Does anyone have an answer for this????