With both blocks being aval. do you also use a supplement ( coat, hoof, joint, all in one, ect) in your pellet food or just the pellet food and the 2 blocks??
There's a lot that goes into your question. Primarily, you need to determine if you are providing YOUR feed to manufacturer's recommendations according to the weight and class of your horse. If you are feeding just a handful or so of pelleted feed (or sweet feed, or oats, or corn) to your adult 200 lb mini, then he/she is likely NOT receiving the full benefit (i.e. all the vitamins, minerals, and protein that the bag says he is getting) of that feed. So many times we CAN'T feed our minis the recommended amount because they would get too fat. Feed not only provides vitamins/minerals/protein, but also CALORIES. Remember, most feed manufacturers' formulas are designed with full size horses in mind, not our air-fern minis. In order to get all the good stuff supplied in the feed, you have to provide it to your horse as recommended by the manufacturer BY WEIGHT, not volume (a can of this, a scoop of that).
If you are feeding a highly concentrated, nutrient-dense feed like a ration balancer (Buckeye Grow N Win, Progressive ration balancer, Purina Born To Win, TC-30, even Triple Crown Lite), then you would only have to feed 4-6 oz PER DAY to get the guaranteed analysis (what the feed promises to deliver). Other feeds might require you to feed 1 lb or more per day to a 200-250 lb horse. What may happen in this case is your horse gets fat, so you cut back on the grain. At that point he may lose some weight because you've reduced the overall calories, but he MAY NOT be getting enough vitamins or minerals from the feed any longer. You
can reduce the amount of your favorite feed, however, to just a handful or a cupful as long as you put back (supplement) the important parts -- the vitamins and minerals. Don't depend on your horse to think that out for you, however -- play it safe by putting it right on their feed once or twice per day. The bag instructions will tell you how much to "top dress". In addition, you can still leave a low-powered free choice mineral out for them to munch on when they like. As stated above, some of these blocks disappear VERY quickly. There is a lot of research which states this happens primarily because the blocks taste good, not so much that the horse is mineral-seeking (though he will seek out salt and phosphorus). If you find your horse chowing down on a mineral block, you might offer it intermittently rather than leaving it out free choice -- more like a treat -- and continue to top dress the Purina 12:12 (or similar product) daily when feeding less than the manufacturer recommends.
As far as supplementing with other products with specific targets (coat, hoof, joints), this can be done on a horse-by-horse basis. These type of products don't normally compete with or significantly repeat what is in the average feed. Coat products provide essential fatty acids or a fat source, hoof products generally contain amino acids/protein, and joint supplements contain neutriceuticals like chondroitin, glucosamine, MSM, and hyaluronic acid that aren't typically found in feeds. It never hurts, however, to review the ingredient list from your feed and supplements to be sure you aren't overloading in any department. This is particularly true of selenium which is easy to overdose. Most feeds are fairly low in selenium, but SOME are not. The average vitamin/mineral supplement is low in selenium, but SOME are not. It's a good idea to do the same type of label-reading for things you feed to your horse just as you would when choosing grocery items for yourself.
Robin C