I Don't know where your yard is, but I used to pay 90 per month including use of school and excellent grazing, fed am and or pm at no charge. haylage was available at extra cost. I know things are getting expensive but 50 a week is a lot.
It could be the high fibre nuts, check the label. Could be the alfalfa nuts, if you take them out give it 2 weeks to get out of the system. Copra, speedibeet and linseed and or grass nuts. Keep it simple to start.
Have you checked teeth and wormed? Ulcers?
It could be the alfalfa or the conditioning cubes as full of soy (mine reacts to soy) (check ingredients). Definitely ditch the mix!
I feed.. Equilibra balancer, handful of molichaff, (don't be afraid of a little sugar, people have become silly over...
Pink mash or topspec high fibre mash. Both companies will send you a sample if you email them. I looked into it for mine, he loves the high fibre mash but not the pink.