My coop is next to my garden and the chickens are allowed into my garden all year, except during planting/early growing season. Once plants are established, they didn’t do much damage and devoured bugs. They sampled some things, like blackberries, but I grow enough to allow for their snacking. Their time in the garden is limited to when I’m out there, but that’s be because of predators.
I found they really didn’t like walking on black plastic sheeting, so those beds that I used it on they left alone. I suspect they’ll get used to it eventually but worked well this summer.
I initially worried a lot about them destroying things, but they were surprisingly polite about it all, even walking mostly on the paths. They were great helpers when I’d be weeding - gobbling up bugs and grubs while I pulled up the weeds.
I also worried a lot about them eating things that are supposedly toxic to them, but they left those alone too (beans, green tomatoes, etc).
Mine won’t eat squash bugs or cucumber beetles which was a major disappointment, as I have a lot of those every year. They love japanese beetles, but I had to teach them how to find them (in the marigold blooms).
Chickening + gardening is my favorite hobby. I love to have them around me when I’m working out there!