Can Deer Eat Hay?

During the winter, deer are natural browsers. For them to switch to a diet of hay can be deadly if it happens all at once.

Haystacks are a great attraction to big game animals and it seems that every rancher has a story about mule deer that fed at their haystacks and were soon found dead with stomachs full of hay. This leads to the conclusion that deer cannot digest hay (alfalfa) and that feeding deer hay will kill them.

This isn’t true, but it takes a bit of understanding of how deer digestion works in order to explain why deer sometimes die with bellies full of hay.

Deer are particular eaters. Unlike elk that can eat and process rough grasses just like cattle, a deer’s digestive system is not able to process coarse foods fast enough. Deer select tender grasses, forbs, leaves and flowers that are lower in cellulose content for the mainstay of their summer diet. These can digest quickly in the four-chambered stomach of the deer with the aid of microorganisms in the rumen.

The microorganisms in the gut are responsible for most of the digestion. The deer consumes the food and later chews the cud in order to pulverize the food particles but the tiny organisms actually digest it into useful nutritional products for the deer.

During the summer months, the rumen microorganisms that specialize in digesting leaves and forbs increase to match the intake of the animal. Microorganisms that are better at digesting stems and twigs decline because they aren’t fed.

As fall approaches and the deer’s diet gradually shifts more to browse (brush) the microorganisms that digest this food source begin to increase. As leaf and forb intake declines, the commensurate microorganisms fade to background levels. So, there is a shift of microorganism colony dominance.

That is the crux of the can/can’t eat hay dilemma. Which colonies of microorganisms are dominant at the time? In mid-summer when the numbers of leaf digesting microorganisms are high, deer could live exclusively off alfalfa hay, dried or fresh. Even later in the fall, if a deer could eat just a little hay each day for a week, the colonies of leaf/forb digesters would expand and ultimately, the deer could thrive on hay.

The trouble happens when a deer comes to a haystack after having been on a diet of browse or near starvation and gorges on hay. There are not enough of the right microorganisms to process the hay and the entire digestive system gets corked. By the time the microorganisms can organize and reproduce to take advantage of the bounty, the deer is dead.

So, to the question of winter feeding of hay to deer. Can it be done? Sure. But there are a lot of stars that need to align first. If managers can predict what the weather will be in the middle of January AND how long the winter will last AND given dire weather predictions if they can start feeding well before there is trouble to condition the deer to the feed AND if they can find high quality hay AND if they can get the food to where the deer winter AND if they can keep elk and deer separate so the deer actually get the food AND if they can keep the adult deer from driving off the fawns AND if they can keep the effort up all winter, then feeding deer hay isn’t a problem. But those are a lot of problems to overcome.

Native forage that deer have survived on for eons is clearly the better answer to the question of how to feed deer.


Help Idaho Wildlife

When we traveled across the state in October 2017, most of the vehicles we saw using the wildlife management areas did not have wildlife plates. Buying wildlife plates is a great way for non-hunters and hunters alike to support wildlife-based recreation like birding.

C'mon folks, let's help Idaho's wildlife by proudly buying and displaying a wildlife license plate on each of our vehicles! 

See below for information on Idaho plates. Most states have wildlife plates so if you live outside Idaho, check with your state's wildlife department or vehicle licensing division for availability of state wildlife plates where you live. 

And tell them that you heard about it from!

Wildlife License Plates

Idaho Wildlife license plates provide essential funding that benefits the great diversity of native plants and wildlife that are not hunted, fished or trapped—over 10,000 species or 98% of Idaho’s species diversity. Game species that share the same habitats (such as elk, deer, antelope, sage-grouse, salmon, trout) also benefit from these specialty plates.

No state tax dollars are provided for wildlife diversity, conservation education and recreation programs. Neither are any revenues from the sale of hunting or fishing licenses spent on nongame species. Instead, these species depend on direct donations, federal grants, fundraising initiatives—and the Idaho Wildlife license plates.

Both my vehicles have Bluebird Plates. I prefer the bluebird because the nongame program gets 70 percent of the money from bluebird plates, but only 60 percent of the money from elk and trout plates - 10 percent of the money from elk plates supports wildlife disease monitoring and testing programs (to benefit the livestock industry) and 10 percent from cutthroat plates supports non-motorized boat access.

Incidentally, in 2014, the Idaho Legislature denied the Department of Fish and Game the ability to add new plates or even to change the name of the elk and cutthroat plates (very specific) to wildlife and fish plates, a move that would have allowed for changing images occasionally and generating more revenue. It would seem that they believe that we Idahoans don't want a well funded wildlife program.

I think it is time we let the Legislature know that Idahoan support wildlife funding and that we would like to see these generic plates come to fruition.

"WOW. What a phenomenal piece you wrote. You are amazing." Jennifer Jackson

That is embarrassing, but actually a fairly typical response to my nature essays. Since The Best of Nature is created from the very best of 16 years of these nature essays published weekly in the Idaho Falls Post Register (online readership 70,000), it is a fine read. It covers a wide variety of topics including humorous glimpses of nature, philosophy, natural history, and conservation. Readers praise the style, breadth of subject matter and my ability to communicate complex and emotional topics in a relaxed and understandable manner.

Everyone can find something to love in this book. From teenagers to octogenarians, from the coffee shop to the school room, these nature essays are widely read and enjoyed.

Some of the essays here are my personal favorites, others seemed to strike a chord with readers. Most have an important message or lesson that will resonate with you. They are written with a goal to simultaneously entertain and educate about the wonderful workings of nature. Some will make you laugh out loud and others will bring a tear to the eye and warm your heart.

Readers Write:

"You hit a home run with your article on, Big Questions in Nature. It should be required reading for everyone who has lost touch with nature...great job!" Joe Chapman

"We enjoyed your column, Bloom Where Planted. Some of the best writing yet. The Post Register is fortunate to have your weekly columns." Lou Griffin.

To read more and to order a copy, click here or get the Kindle version 


Copies are also available at:

Post Register

Island Park Builders Supply (upstairs)

Barnes and Noble in Idaho Falls

Harriman State Park, Island Park

Museum of Idaho

Valley Books, Jackson Wyoming

Avocet Corner Bookstore, Bear River National Wildlife Refuge, Brigham City, Utah

Craters of the Moon National Monument Bookstore, Arco, Idaho