well to buy in big bale square haylage costs around £25. With 4 horses on it adlib we expect to go through a bale every 7 days, so would cost approximately £6.25 a week or £27 a month.
From that a round figure of maybe £30 a month? Although saying that I used to pay old YO £10 a week which still worked out cheaper for me than buying small bales.