Remembering that the horse is a hindgut fibre-fermenter and should only eat grass forage, there is no feed-brand finer, in my humble opinion, than the Agrobs Pre-Alpin all-natural, chemical-free, multi-diverse bavarian grass fibre range.
With 3.5 metabolics in our herd (Murphy, Cookie, MacAttack and most recent herd member, Pops, a possible meta-risk), they all get a small scoop of the Agrobs' Weisenflakes, just simple, compressed, grasses. They also do a larger 'cob' - their Weisencobs - the Weisenflakes are simply sliced up Weisencobs , just with less soak time.
I also chuck in a handful - literally a handful - of Agrobs' Leitchgenus chaff, nicknamed 'Fatties Chaff', which is a combo of super-low starch grasses and straw (which gives them their lignan woody-fibre) coming in at just under 2%. I like to include a bit of chaff in the feedbowl because it lengthens the chew time which creates saliva which helps buffer foregut acidity, plus it keeps them occupied for a longer.
None of my local feed merchants sell it so I get it online via EquiSupermarket - https://www.equisupermarket.co.uk/nutrition-horse-feed.irc?brand=6000518 who usually deliver within 2-3 days.
This combo makes makes up my (perfect) base feedbowl carrier.
My routine? I'm very lucky - I've now hung up my reins and the horses and I are now happily retired together, so they all live out permanently on around 7-acres of ancient sheep moorland grasses, which I split into summer/winter fields, with roomy field shelters that we've put up. When I arrive I go straight to my feedroom - a knackered old caravan next to the shelters - and dish up the Weisenflakes' scoops into each feedbowl. In goes the water and a slosh of ACV, and the soak begins while I then head off to do their hay which takes around 10-15 mins. Hay done, and it's back to the van to finish off with the essential nutrients to balance their body chemistry.
Top Tip - to make life easier I actually feed our 3-in-1 VitaComplete all year round which combines our EquiVita, salt and linseed blended into one supplement. This saves having the extras in my feedroom to measure in - https://equinatural.co.uk/c/online-shop/mineral-solutions-equivita-and-vitacomplete/vitacomplete-range-our-3-in-1-convenience-range-wi
The above is what I consider non-negotiable, then I add in some extras, just my own personal choice:
ACV - I order it from EquiMins, 5-litres for around £8.00. If you're ordering it, make sure to get the one with the horse photo on the front - the one with the chicken is more expensive yet it's the exact same product (insider knowledge!)
Now to their herbs. Murf, Cookie and MacAttack get our MetaTonic, although come Spring MacAttack gets a combo mix of our MetaTonic and SwItchTonic for his chronic sweetitch in summer. Pops gets our MetaTonic and MellowMare, as, through much trial and more error, we now know she badly needs seasonal/hormonal balancing. Carms gets our JSTTonic as she's officially 2/10 lame having been born with a twisted hoof.
So there we have it: Agrobs Weisenflakes & Leitchgenus chaff, our own EquiVita forage-balanced minerals, micronised Linseed and salt (or VitaComplete for convenience), ACV and their respective herbs.
The historic paddock of 30-years plus ago would have 30-40 different plants and grasses, growing long and intermingling with meadow herbs - I remember the days back in the late 1960s/early 1970s, where we'd turn out the riding school ponies onto those lush, untouched pastures every Sunday night for the week before bringing them back in the following Saturday morning for the weekend's work. Laminitis? Cushings? Metabolic Syndrome? Unheard of ...
Agrobs blend together over 50 organic different grasses and natural herbage from the Bavarian hillsides, and include everything in their range from meadow grass cobs, a pregnant/nursing mare and youngstock range, and a lovely PreAlpin Senior chaff to name just a few.
Where they really shine, for me anyway, is their dedicated chaff for our metabolic horses, their Leitchgenus, composed of untreated wheat straw and green oat grass, super-low on the starch front at less than 2% - this makes it ideal for the EMS/IR equine. It’s also the lowest in their range of naturally occurring iron/manganese.
NB. Can I just add here that my recommendations don't mean these are the only feeds I'd feed that are out there; there may be many other independent growers and producers who aim for clean forge feeds. It could be that I've either tried and declined, or rather, my horses have. It could also be that I've simply not come across them - either way there's no intention on my part to specifically exclude any feed brands here.
My preferences are simply my own personal feed choices and recommendations, which have proven to work well for my own horses' health.