Grass vs Hay

At what point do you decide it’s not worth it to feed the animals grass anymore? I keep making grass starters, and then they just eat it immediately anyway, or it’s on the other side of my farm and they don’t eat it, but it’s nowhere near enough to fill my silos for the winter, so I have to buy hay anyway, so why don’t I just feed them hay in the first place? Except hay ain’t cheap, so is it better to just figure out the grass situation…

Is the haymaker sword the solution?? And why doesn’t Marnie have a subscription service??