Mine are really not great at weeding. They seem to like the undergrowth.It's a big run at present with only five hens, but it'll feel smaller next year if pullets hatch.
There's more garden than I can cope with and once a secure front fence is in place, the hens will be helping with all the weeding in the front garden that I can't make time for. They've been extremely good at weeding so far. The weeds used to be higher than my head where the run is and they've done a great job eating them up while nourishing the soil and laying eggs. They've been brilliant.