When I was growing up, we fed Alfalfa free choice (sometimes it was alfalfa/mountain timothy mix) and/or alfalfa cubes (purchased in loose bulk and stored in large tanks, not bagged) and never had the problems that we supposedly should have. But our horses did not get a lot of concentrated feed and were out on pasture as well. We also didn't have the show type QH, Paints and Apps that were coming into favor as halter/pleasure horses either. Maybe it made a difference.
I'm currently feeding our penned (dry lot) ponies alfalfa pellets (in 1 pasture - 3 2014 stud colts & 2 2010 geldings; 1 pen - 3 yr old stud colt; 1 pen - 6 yr old mare). Because I feed concentrated, pelleted feed wet - I fed the alfalfa pellets wet. I do feed the alfalfa pellets in separate buckets - as I try to keep them almost free choice unless they show signs of being overweight. None of my ponies currently getting alfalfa pellets is near the age of yours, though.
A couple of months ago I started working earlier and can't feed them wet before I go to work. SO, I started feeding the 5 boys theirs dry and fed quite a bit after they got used to eating it that way. (5 ponies under 38" of height were getting 21 #s of alfalfa pellets daily and cleaning them up completely along with free choice coastal hay from round bales and pasture). As they gained the weight I wanted them to gain, I've cut them back. They were down to about 12# - but with less the 2 older, slightly larger geldings were getting more of the pellets and the yearling, smaller colts were getting less. This past week, while out on pasture that's been w/o ponies on it for a month and was knee deep in grass (ok, and weeds), I haven't fed them any alfalfa pellets - but will be moving them back to their pasture where there isn't so much grass and will re-introduce pellets - dry. These boys look better then they've looked in years!! The oldest two are 4 yr olds. The youngest is not quite a full year old yet. The penned stud is fed 14 #s at a time and when his bucket is empty - I add more. The penned mare gets the least - just a little over a # and no longer free choice, but she gets that amount 2x daily.
I still use the beet pulp shreds but have two friends who swear by the beet pulp pellets. You might give them a try. Also, Tractor Supply now carries a WIDE assortment of "chaff hays" - hay already shredded and bagged. I haven't read all the specs on them, since I haven't felt I've needed them, but they are out there and there are many different kinds.
I have not used them, but you can try also to use a "hay pillow" - which has much smaller openings and is put on the ground for feeding hay. It's a type of hay net - and from what I"ve heard even mini foals don't usually get their hooves caught in them. I now use the much smaller "slow feed" hay nets, and none of the slightly larger ponies here have had problems with it and I use them now for Julie's much smaller mini stud... I also was hanging the hay nets w/ attachments on both sides so that the bag hangs much higher to try to keep them from hanging their hooves in them.
As to feeds, you can try different types until you find one that your fellow likes and does well on. I found that a Southern States, Legends Sr Feed worked best for mine when I was feeding Sr feed. Ours didn't like and didn't do well on the Purina Sr feed. The formulation for both types has changed since I last fed them, so I don't know how either would work now for our ponies.
EDITED TO ADD - some alfalfa pellets are dusty. They become dusty as the pellets break down. Standlee AP are much harder due to the way they are made and also come 10 #s less to a bag. With the amount of pellets that I feed, I prefer the Southern States AP - they aren't as hard, and they are a bit more dusty (I do not stand over the bins when I dump the bags in, nor do I let the ponies stick their noses in the buckets when I pour the dry pellets in as they will start coughing). But I get 10 more #s per bag and the ponies like the softer pellets better - both dry and wet. Watch as some alfalfa pellets are made with additional products including molasses (to keep the dust down) - both Standlee and the Southern States alfalfa pellets do not have any additives.