Trialing a probiotic in the henhouse
Maple Wind Farm is inoculating their winter-laying houses with Lactobacillus, a beneficial bacterium, to improve animal health. It’s an on-farm trial in collaboration between the farm and the Land Care Cooperative, a farmer-led group focused on building healthy, water-retaining soils, reducing flood risks and promoting biodiversity.
“What we saw and observed was really significant with this. It kind of blew me away, quite honestly,” said Lindsay St. Pierre, a longtime Maple Wind employee who helped design the Lactobacillus trial. She discussed the trial at the 2026 Northeast Grazing & Livestock Conference.
Maple Wind is a multispecies pasture-based livestock farm located in Richmond, VT. They manage layers, broilers, turkeys, pigs and cows on 180 acres of grassland.
During the grazing season, they rotate their flock of 1,500 layers within the pasture system. From November through April, the layers are shifted into two 30-by-100-foot hooped structures where they’re managed in a deep-bedded pack system of peat moss and hay.
“They do not have winter or outdoor access through that time,” said St. Pierre.
Lactobacillus, a probiotic, is used in the fermentation of human foods like yogurt, cheese, sauerkraut and kombucha. Maple Wind uses five ingredients – water, rice, milk, Sea-Crop® (concentrated minerals of seawater) and molasses – to brew a Lactobacillus-rich concentrate.
First, St. Pierre mixes one quart of uncooked rice to one gallon of water. In three days, it is bubbly with a sour smell. Then, she adds strained fermented rice water to two gallons of room temperature milk, adding two tablespoons of Sea-Crop. She keeps this mixture at 65º – 75º and within one to three days a cheese-like substance and whey form.
In the final step, she strains the “cheese” from the whey and adds one gallon of water and one quart of molasses to each gallon of whey. She stores the finished concentrate, about five gallons using this recipe, inside where it doesn’t freeze.
The bucket lasts six months because they dilute the concentrate to a 200:1 ratio before spraying – about a quarter-cup into two gallons of water.
St. Pierre or another employee sprays the diluted concentrate with a two-gallon handheld manual sprayer, one gallon per house. The Lactobacillus solution is misted throughout the entire laying house environment, specifically on the bedding, roosts, feed line and nesting boxes. When temperatures are not freezing, misting fans with intermittent timers are likely the lowest labor/highest impact application method.
According to St. Pierre, spraying Lactobacillus in the winter layer houses helps to maintain a balanced environment by keeping harmful pathogens in check. She said, “It’s a net positive on animal gut health. So it’s the same thing as us, why we eat kimchi and fermented foods. It’s really just increasing their overall health, basically.”
St. Pierre observed multiple benefits to the trial: a dramatic reduction in ammonia and odor, especially during freeze/thaw events; a noticeable decrease in mortality; eggshell quality stayed more consistent through winter conditions than in previous years; the lay rate remained at 75% despite seasonal stress; and the layers were calmer and more settled, with fewer stress-related behaviors.
She noted that these observations were anecdotal, but that there is a growing body of research that supports the use of beneficial bacteria in many areas of livestock agriculture. Research supports her observations; studies have shown Lactobacillus can bolster hens’ immune systems and help protect against avian influenza.
During summer, the bedded pack is removed and the houses are power-washed and then sanitized. They begin spraying Lactobacillus about a month before the layers are transitioned into their winter quarters. The goal is to populate the environment with beneficial bacteria before pathogens can establish in the houses.
St. Pierre encourages other farmers using bedded packs for any kind of livestock to try using Lactobacillus spray to promote animal health. She said, “Especially as we see more freeze/thaw cycles through the winter in the Northeast – hello, more moisture! We see this as a proactive approach to making sure our animals and their environment are as healthy as possible.”
by Sonja Heyck-Merlin
