Free Choice Feeding

I want to take a break from the mineral topics to address something about which I have been getting many questions.  The issue is free choice feeding of hay.


More specifically, it has been suggested that horses with insulin resistance must have unlimited access to hay around the clock and claimed that even a few minutes without hay is dangerous to them.  The rationale is that being deprived of access to food is unnatural and constitutes a stress, causing cortisol release.  The cortisol release in turn will worsen or perpetuate insulin resistance. A further claim is that this stress and cortisol release will lead to acute, chronic or recurrent laminitis.

This  is dangerous advice that has no basis in fact and attempts to simplify what is not a simple situation.

The most important consideration with regard to hay, IR and laminitis risk is the sugar and starch content of the hay. Whether fed in limited amounts or free choice, this is what determines the insulin response and therefore how safe (or not) that hay is.

While obesity per se does not causing insulin resistance, it does worsen it. Overweight IR horses improve with weight loss. Severe calorie restriction below 1.5% of bodyweight on the average can backfire because this metabolic stress actually triggers or worsens IR, but unlimited access won’t work either.

This is because insulin resistant horses are also leptin resistant. Leptin is a hormone that controls calorie  intake by shutting off appetite when sufficient energy/calories has been consumed. The IR horse does not have this regulation. Allowed to eat all that they want, the IR horses will become even more obese.

The solution for IR horses is a slow feeding system. There is now a wide variety of options  to do this, including nets with very small openings or feeders using bars and grates that limit how much hay the horse can extract.

Free choice hay feeding usually does work very well for horses that are not metabolically challenged.  After a few days of adjusting to the novelty, they will regulate their intake to what they need. It’s not an option with grains or complete feeds containing grains though. The palatability of these dietary items will lead to overconsumption.

My starting point for feeding IR horses is a hay with no more than 10% ESC (simple sugars) and starch, combined, fed at 1.5% of current weight or 2% of ideal weight, whichever is larger. A slow feeding system is ideal. Alternatively, the horse is fed multiple small meals throughout the day.

Dr. Kellon

About Dr. Kellon

Graduate of University of Pennsylvania Veterinary School. Owner of Equine Nutritional Solutions,, industry and private nutritional consultations, online nutritional courses. Staff Veterinary Expert at Uckele Health and Nutrition.
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12 Responses to Free Choice Feeding

  1. Stephanie Dobb says:

    I have 7 Icelandic horses on dirt and gravel pastures, their weights vary, some are more motivated by food than others. 2 of the 7 are IR horses, therefore I only feed tested hay, at the moment the lowest sugar hay in my area is a timothy mix with 20% alfalfa. I buy my hay from a lady that specializes in IR horses so I’m confident it is adequate. I’ve just purchased some slow feeders (wood box with metal grate style) and am wanting to try the free choice method of feeding. I noticed timothy was mentioned above as a possible problem with free choice feeding. What are your thoughts? On average, how long does it take for the initial weight gain to come off? Should the horses be exercised more during the weight gain time? Is the weight gain actually “fat”, or is is more of a “hay belly” weight gain? I’m excited to try free choice feeding, partially because feeding 7 horses will be easier for me, plus less waste due to the slow feeders. Also, I’m hoping those that are eating the tree bark in the fields will stop. Thank you for your knowledge 🙂 Stephanie

    • uckeleequine says:

      The type of hay per se isn’t a problem with free choice feeding. The main reason it might not work is if there are insulin resistant (IR) horses because they do not have the normal ability to regulate their intake. Slow feeders can solve this problem by limiting how much the horse can eat. The grate system has a lot of advantages but the openings in the grate are sometimes too large to really restrict intake. You will have to watch weights carefully.

      I wouldn’t expect a slow feeders system to necessarily cause weight loss unless you limit how much is put out each day but with this many horses with different needs that would be difficult to do. You will need exercise for weight loss. Yes, the excess weight is fat.

      As a starting point for how much to put out each day, add up the body weights of all the horses, using the ideal body weight rather than actual for any that are overweight, and feed 2% of that per day – i.e. 20 lbs of hay for every 1000 lbs of horse weight.

      Dr. Kellon

  2. libby thorman says:

    Does this apply to horses living out 24/7 365?

    • uckeleequine says:

      Yes, it does. If you have a horse that gains too much weight living out 24/7 you will need to muzzle them if on pasture or use a slow feeding system for hay.

      Dr. Kellon

      • libby thorman says:

        how very interesting. will work on my slow feeder that can have enough in it to never run out 🙂 Thank you

  3. Shirley Johnson says:

    I am puzzled at to why if my horse weights 960 and I want her to be at 900 why would I feed her 18 lbs (2% of ideal wt) which is more than she’d get at 1.5% of current body wt. I think I’m missing something, probably my brain?? Thanks for the explanation as I never did understand this.


    • uckeleequine says:

      The goal is to provide enough calories to support the ideal weight without causing metabolic stress by underfeeding that the horse’s body would read as “starvation” and trigger an insulin resistant response. When feeding a low sugar/starch hay the calorie content is usually within the framework of 2% of ideal weight to maintain that weight. We don’t want to go below that. If the horse is grossly obese and 1.5% of body weight is actually higher than the % of ideal bodyweight it’s best to use that as a starting point to avoid metabolic stress.

      Worsening IR or not, you can get weight loss by severely restricting calories. However, the weight loss per se is not the issue. It’s the IR and laminitis risk we’re concerned about.

      Dr. Kellon

  4. Don’t you think it would be a good idea to define “hay” here? Free feeding of bermuda grass is significantly different that free feeding of alfalfa or timothy. While I am in total agreement about slow feeders (replicating the slower grazing process) not all hays are created equal and most readers will not be able to determine a 10% ESC level.

    • uckeleequine says:

      Bermuda hay is not automatically safe versus timothy or alfalfa. There can be issues with alfalfa in individual horses even when the sugar and starch levels appear safe but we don’t really know why that is the case. For other grass hays, timothy, orchardgrass, etc. you need to have the hay analyzed. The rule of thumb is that the combination of starch + ESC (simple sugars) should be less than 10%. Very sensitive horses may need it lower.

      Dr. Kellon

  5. Thanks or clarifying the situation. My horse is IR and I had read the aforementioned information and wondering if I was doing right by my horse.

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