I think a lot must depend on what type of chickens and what they get fed otherwise. They probably do, but I've never actually seen my chickens eat grass, I have mostly tall fescue here. They do like chickweed and henbit but other than that I seldom see them eating anything green. They seem to mostly be looking for flowers, seeds and insects.
To me, "flowers & seeds" also represents green while free ranging. Though may be better linked to grains.
I have learned over the years, on this property, that I lose significant #s of birds if totally free ranging or even using poultry netting. The result - various tractors - for chicks/growouts, for meat birds, for laying hens. What I have found is that each time a tractor is moved, you can throw down seed. You can choose the seed and do a mix of those higher eligible ones found to be consumed in the charts depicted in research (previous reports - pics).
On our sandy soil, w/o irrigation or supplemental watering, a lot won't grow at first. But w/ each re-occuring run of tractors, as the soil composition is changed, different & more seeds are growing & yes, w/I the tractors the birds do consume the grasses OR the seed heads/flowers if they are that far along (along w/ free choice feeds in containers or feed dropped on the ground in the tractors 2x daily).
Also, i have primarily used tractors in my "front yard" - not sure acreage but HUGE to most (as well as me). The yard is sloped - from the pasture "down" to the house. I have no idea how much of a slope - wasn't even really noticed when we bought the property. Never thought to be a problem until 2016 & the first hurricane dumped MANY inches of rain. The water ran down, covering most of our green walking path & lapping up the 1st 2 steps up to front porch.
Get to 2018, when I started running tractors. Each year, there has been a huge change. This year, up until June, there have been large amounts of up to 7" in one rain event. No longer get running water down slope. No water lapping over stairs. We have not had a "major" hurricane since 2016, but i suspect even if "oversturated ground" is overloaded then w/ another 11" rain event, our front yard wont be oversaturated & the changes in the soil & the fruit trees planted thus far, will catch that runoff long before it reaches our steps & walkway (now also being turned into a drive area around & straight up from steps making a figure 8 around the yard. Not cement, asphalt or gravel, but cardboard & shredded paper & woodchips. Like garden pathways, but wide enough to drive on/through.
HUGE amount of growth of grasses & weeds that now require major amounts of mowing as well as tractoring birds. In 2022 & 2023, I also put in 5 raised garden beds. I started by using them as compost areas & growout for chicks. Unfortunately, due to life, work & health issues, they have yet to actually be planted...You can tell where there are no birds/tractors as those areas are still sandy w/ little to no grass growth. The growth of fruit & other trees between or around garden beds & tractored birds is darn near scary & REALLY hard to comprehend when you look back to when we closed on this house in December 2014...
The amount of feed that we have to feed varies, depending on what time of year we are talking about. We do get a little snow here, but more often get ice storms - they get free access to feeders then & sometimes fermented feed or wet mash.
Right now I have 3 chickens vs the just under 100 in both 2018 & 2022/23...
