The best feed through fly control for horses is a consistent, diflubenzuron-based pellet.
Flies drain energy, spread germs, and make even a quiet gelding twitchy. If you run a barn, you know the struggle. Sprays help for a day. Masks slip. Traps catch some but not enough. That is why feed-through fly control has become my go-to base layer. It targets larvae in manure, where flies breed, so your horses can relax. In this guide, I compare top options and share what actually holds up all season. If you want the best feed through fly control for horses, start here and layer smart for calm, clean aisles and happier rides.
Formula 707 MultiFly Feed-Thru Fly…
EFFECTIVE – Contains active ingredient Novaluron, which is an Insect Growth Regulator. This new generation technology is 99.9% effective at breaking the fly life cycle to help eliminate the fly…
Formula 707 MultiFly Feed-Thru Fly…
EFFECTIVE – Contains active ingredient Novaluron, which is an Insect Growth Regulator. This new generation technology is 99.9% effective at breaking the fly life cycle to help eliminate the fly…
Farnam SimpliFly Feed-Thur Fly Control…
Feed-Through Fly Control for Horses: SimpliFly breaks and prevents the fly life cycle in manure, helping reduce stable fly populations and providing reliable fly control for horses in barns, stalls,…
Formula 707 MultiFly Feed-Thru Pellets, 5 lb
This 5 lb bag from Formula 707 is a simple way to trial feed-through control in a small barn or with a few horses. The pellets are made to be palatable, so most horses eat them well when mixed into grain. The goal is to break the fly life cycle in manure, which is where the real battle is. When used daily, barns often see calmer tails and fewer bites in a few weeks.
I like this size as a starter or for travel season. You get 91 servings, which makes it easy to test on one or two horses. It is also a handy backup if you run low mid-season. If you want the best feed through fly control for horses without a big upfront cost, this is an easy step.
Pros:
- Starter-friendly 5 lb size with about 91 servings
- Palatable pellets that blend well with grain
- Targets fly development in manure for barn-wide impact
- Good for testing before buying larger sizes
- Pairs well with sprays and traps for layered control
- Helps reduce stable and house fly pressure over time
- Clear daily-use routine builds consistent results
Cons:
- Smaller bag may cost more per serving
- Needs daily, consistent feeding for best effect
- Not a quick fix for current adult flies
My Recommendation
This 5 lb bag suits small barns, new users, and horses who need a slow, steady start. If you have one or two easy keepers, this size is efficient and low risk. Use it early in spring for best results, and keep your manure area clean. For many, it ranks among the best feed through fly control for horses when you want to test and see steady gains.
It is also a smart travel bag if you show. Keep your horse on the same routine on the road. For value, the 5 lb bag works best for one horse. If you confirm it works, move to a larger size to save per serving.
| Best for | Why |
|---|---|
| Small barns or single-horse homes | Low upfront cost and enough servings to test results |
| Horses picky about taste | Palatable pellets blend into daily grain well |
| Show and travel use | Compact size fits in a trunk for consistent feeding on the road |
Formula 707 MultiFly Pellets, 10 lb
The 10 lb MultiFly is the better choice if you have two or more horses. You get roughly 182 servings, which supports steady use across peak months. The pellets are easy to dose and blend into feed, so your routine stays smooth. With daily use, you choke off fly breeding where it starts.
I suggest starting before flies surge in spring. Keep it up through fall for a calm barn. If you want the best feed through fly control for horses in a busy aisle, this size delivers. It also helps you save per serving over small bags.
Pros:
- Cost-effective size for multi-horse barns
- About 182 servings for long-term use
- Pellets are easy to mix and dose
- Supports a barn-wide fly management plan
- Great base layer with masks, fans, and traps
- Consistent feeding builds stronger results over weeks
- Helps reduce stress and tail swishing in the aisle
Cons:
- Requires daily feeding to maintain effect
- Not a stand-alone solution for heavy adult fly swarms
- Storage needs a dry, sealed spot
My Recommendation
Choose this 10 lb bag if you manage a small to medium barn and want a steady supply. It hits a sweet spot on price per serving and convenience. When paired with pasture cleanup and airflow, it stands out as one of the best feed through fly control for horses for most stables.
I like it for families with two to four horses. The bag lasts, and you build momentum before fly season peaks. Over summer, you should notice calmer grooming, fewer head tosses, and easier stalls.
| Best for | Why |
|---|---|
| Two to four horses | Balanced cost per serving and enough volume for a full season |
| Barns layering control | Works well with fans, masks, and traps for strong results |
| Owners who want simple dosing | Pellet form mixes fast with grain and reduces waste |
Farnam SimpliFly, 10 lb (160 Days)
Farnam SimpliFly is a well-known feed-through that uses an insect growth regulator to stop larvae from maturing in manure. In plain terms, it breaks the life cycle before flies become a problem. The 10 lb tub offers about 160 days of coverage, which suits a single horse or a duo for part of the season. It is a staple in many barns due to its steady, predictable results.
I have seen good results when owners start early, stick to daily feeding, and keep stalls clean. This is not a spray; it will not drop adult flies on contact. It works beneath the surface by reducing the next wave. If you want the best feed through fly control for horses with a long track record, SimpliFly stands tall.
Pros:
- Respected brand with years of use in barns
- Targets larvae to reduce future fly populations
- Clear dosing and easy mix-in with grain
- Fits a one-horse, full-season plan
- Pairs well with spot sprays and physical barriers
- Helps stabilize sensitive skin by cutting bites
- Backed by strong user feedback over many seasons
Cons:
- Must be fed daily without gaps
- Not a cure for adult flies already swarming
- Results depend on manure management and turnout habits
My Recommendation
Pick SimpliFly if you want a proven formula that fits straight into a daily ration. It is ideal for riders who prefer a set-and-forget routine and a brand they can trust. Used with barn hygiene, it is one of the best feed through fly control for horses for clear, steady results.
For a single horse, the 10 lb tub is simple and cost aware. For bigger barns, buy multiple tubs or step up to a larger supply. Keep expectations fair: this stops new flies from hatching, and you handle the adults with other tools.
| Best for | Why |
|---|---|
| Owners who want proven results | Long-standing formula with consistent field performance |
| Single-horse or pair households | 160-day supply fits a season when started early |
| Riders seeking easy routines | Simple daily dosing and wide brand support |
Farnam Equitrol II, 320-Day Supply
Equitrol II is designed for long-haul control. The 320-day supply is built for a full season and beyond, which is great for consistent barns. Like other feed-throughs, it uses an insect growth regulator to stop larvae from developing in manure. When used daily, it can steady a program and reduce the peaks that wear horses out.
I like this for barns that commit to one product and want fewer reorders. It supports a “set the tone and stick with it” approach. If your goal is the best feed through fly control for horses with minimal mid-season gaps, this format makes sense. It rewards planning and steady care.
Pros:
- Extended 320-day supply minimizes reorders
- Strong fit for barns that value consistency
- Targets larvae to prevent adult fly emergence
- Simple daily dosing and easy mix-in
- Reduces barn stress from constant swishing and stomping
- Helps protect sensitive skin and bites-prone areas
- Pairs well with manure pickup and pasture rotation
Cons:
- Larger upfront cost than small bags
- Requires dry, secure storage
- Does not address adult flies already active
My Recommendation
Buy Equitrol II if you want a full-season solution with fewer supply runs. It matches barns that plan early and feed on a clock. When part of a layered plan, it can be the best feed through fly control for horses that live in high-traffic, high-turnout settings.
It shines for managers who want to “set it and stay the course.” If that is your style, this product will fit your routine. Think of it as a season pass for calmer horses and cleaner aisles.
| Best for | Why |
|---|---|
| Full-season planners | 320-day supply keeps barns consistent with fewer gaps |
| Busy barns with many hands | Simple routine reduces dosing errors across staff |
| Cost control over time | Fewer reorders often mean better per-day value |
Formula 707 Fly Deny Spray, 32 oz
This is not a feed-through, but it is a strong partner for one. Formula 707 Fly Deny Spray aims for up to 14-day protection depending on weather, sweat, and turnout. Sprays help with adult flies that feed-through pellets do not attack. I use sprays on ride days, during turnout peaks, and on thin-skinned horses.
Use this to fill the gap while your feed-through reduces larvae in manure. It is great around ears, belly, and legs. If you aim for the best feed through fly control for horses, a good spray closes the loop. Layer the two for peace on hot, buggy days.
Pros:
- Targets adult flies that feed-through pellets miss
- Useful during rides and on high-pressure days
- Helps protect sensitive spots like ears and bellies
- Pairs well with masks and sheets
- Reduces stress while feed-through builds results
- Convenient 32 oz size for the tack room
- Handy for guests or new arrivals not yet on pellets
Cons:
- Not a feed-through; needs reapplication
- Longevity varies with sweat and rain
- Scent and feel may bother some horses
My Recommendation
Use this spray as your day-to-day shield while pellets work on the source. It is ideal for show days, trail rides, and horses that hate face flies. If you are serious about the best feed through fly control for horses, a quality spray is your reliable second line.
Think of it as tactical support. Apply before turnout or schooling, then adjust as bugs and weather change. Over time, the combo brings calm to barns that once buzzed.
| Best for | Why |
|---|---|
| Immediate adult fly relief | Acts fast where feed-throughs cannot |
| Show and trail use | Easy to pack and reapply on the go |
| Layered control plans | Complements pellets to cover both ends of the fly cycle |
FAQs of best feed through fly control for horses
How does feed-through fly control work?
It uses an insect growth regulator that passes in manure. Larvae cannot mature. Over weeks, fewer adult flies emerge.
When should I start feed-through pellets?
Start early in spring, 30 days before flies surge. Keep feeding daily until cold weather returns.
Do feed-throughs kill adult flies?
No. They stop new flies. Use sprays, masks, fans, and traps for adult flies.
Is it safe for all horses?
Most healthy horses tolerate labeled feed-throughs well. For mares, foals, or special cases, ask your vet first.
Can I use feed-throughs with other fly controls?
Yes. For the best feed through fly control for horses, layer pellets with cleanup, traps, masks, and smart turnout.
Final Verdict: Which Should You Buy?
For most barns, Farnam SimpliFly and Formula 707 MultiFly 10 lb give the best balance of cost, ease, and steady results. If you want year-round coverage with fewer gaps, Farnam Equitrol II is hard to beat.
Use a good spray as backup for adult flies. Start early, feed daily, and you will get the best feed through fly control for horses across the whole season.
