In the heart of winter, when the days are short and the temperatures settle in for the long haul, feeding sheep becomes about more than meeting basic nutritional requirements. Winter feeding is about supporting warmth, resilience, and steady health from the inside out.
Sheep are remarkably well-designed for cold climates, but their ability to stay warm doesn’t come from grain or added fat. It comes from a quiet, powerful system at work every day: the rumen.
The Rumen: More Than Digestion
The rumen is often described simply as the part of the sheep that digests food—but it does far more than that.
Sheep are ruminants, meaning they rely on microbial fermentation to break down fibrous plant material. Inside the rumen lives a diverse population of bacteria, protozoa, and fungi. These microbes ferment long-stem fiber (like hay), producing volatile fatty acids (VFAs)—primarily acetate, propionate, and butyrate—which are the sheep’s main source of energy.
Here’s the important winter detail:
Fermentation produces heat.
As microbes break down fiber, heat is released as a natural byproduct. This means that a well-functioning rumen acts as an internal furnace, helping sheep maintain body temperature even in cold conditions. The more consistent the fiber intake, the steadier the fermentation—and the steadier the warmth.
The Rumen at a Glance
• Largest compartment of the sheep’s stomach
• Home to beneficial microbes
• Breaks down fibrous plants like hay
• Produces energy and heat through fermentationKey takeaway: Hay fuels fermentation. Fermentation fuels warmth.
picture source by australiansheepenterprise.weebly.com
The Sheep’s Four-Chambered Stomach
-
Rumen – Primary fermentation chamber
-
Reticulum – Sorts and moves feed
-
Omasum – Absorbs water and nutrients
-
Abomasum – “True stomach” (acid digestion)
RUMEN
Largest compartment
Home to beneficial microbes
Where fermentation begins
The rumen is where fiber is fermented—producing energy and heat.
Why Hay Matters More Than Grain in Winter
Good-quality hay is the foundation of winter warmth.
On our farm, we feed a non-sprayed 80/20 grass–alfalfa hay mix. For an average winter in the northern states, we’ve calculated that 5 pounds of hay per sheep per day meets our flock’s needs very accurately.
This amount supports:
- Consistent rumen fill
- Ongoing fermentation and heat production
- Adequate energy without overstimulation
Grass hay provides the long-stem fiber rumen microbes need to thrive, while a modest amount of alfalfa contributes protein and calcium—important for ewes carrying lambs, even though overall activity is lower during winter months.
Grain digests quickly and shifts fermentation in a different direction. While it has its place in certain situations, grain does not support sustained heat production the way fiber does and can disrupt rumen balance if overused. For that reason, we do not offer grain to our sheep.
We do offer small amounts of alfalfa pellets occasionally—as a treat and to gently support protein levels—but they are not a staple of our winter feeding program.
From Hay to Heat
- Sheep eat long-stem fiber
- Fiber enters the rumen
- Microbes ferment the plant material
- VFAs provide energy
- Heat is released during fermentation
This is why free-choice hay matters most in winter.
Winter Nutrition: Less Movement, Greater Needs
One of the most common misunderstandings about winter feeding is the assumption that sheep need less nutrition because they are moving less. In reality, winter often brings greater nutritional demand.
Cold temperatures increase energy requirements, ewes are growing lambs, and the immune system works harder during winter stress. Feeding consistent, high-quality hay allows sheep to meet these needs naturally—without forcing the system.
Minerals & Kelp: The Winter Support System
If hay is the foundation, minerals are the support beams.
During winter, our ewes and ram consume noticeably more minerals and kelp. This increase isn’t accidental. Winter places higher demands on digestion, metabolism, immune function, and fetal development.
We offer free-choice:
- Redmond Selenium 90 salt
- Kelp
Rather than filling large quantities at once, we put out enough to last the flock a couple of days. This ensures fresh offerings, encourages steady intake, and reduces waste. By refilling every couple of days, we allow the sheep to regulate their own intake while keeping minerals clean and appealing.
Minerals support rumen microbes just as much as they support the sheep themselves. When mineral needs are met, digestion is more efficient, fermentation is steadier, and overall resilience improves—especially in winter.
Minerals & the Microbial Workforce
• Rumen microbes require minerals to function properly
• Efficient microbes = efficient fermentation
• Efficient fermentation = better digestion and warmthHealthy microbes support a warm, resilient sheep.
What Feeding for Warmth Looks Like on Our Farm
Feeding for warmth isn’t complicated, but it does require consistency and observation.
We watch for:
- Steady body condition
- Calm behavior at feeding time
- Regular rumination
- Sheep that remain comfortable and active during cold snaps
When these signs are present, it tells us the system is working.
Supporting the Sheep’s Design
Sheep don’t need us to reinvent winter feeding. They need us to work with how they were designed.
By prioritizing high-quality hay, respecting the role of the rumen, and offering minerals and kelp free-choice, we support warmth from the inside out—quietly, steadily, and effectively.
Strong winter feeding lays the groundwork for healthy ewes, resilient flocks, and a smoother lambing season ahead.
