most of what chickens bring to the garden party is positive: I've posted this before but it won't hurt to post it again, especially at this time of yearI just worry about the chicken digging vs. shallow-rooted systems of this type of plant.
their poo makes a very valuable addition to the soil around those shallow roots, not just in feeding the roots of the plants above ground but also all the funga and flora that live below it and are usually out of mind because out of sight.