Hen Houses

Delta Waterfowl puts more mallards into every fall flight!

Hen Houses are the most cost-effective tool to increase mallard production. Targeted to areas of the highest mallard breeding density, Delta Waterfowl Hen Houses consistently boost nest success to more than 60 percent. In areas where ground-nesting mallards typically achieve nest success of less than 10 percent, Hen Houses can increase nest success up to 80 percent

Today’s efficiently designed “Supersites” are a direct result of Delta’s extensive research. These clusters of 100 or more Hen Houses are installed in relatively small geographic areas with high breeding mallard densities. Supersites send thousands of mallards into every fall flight, while reducing the cost of labor and fuel to produce ducks.

Delta maintains Hen Houses across the key breeding areas of Manitoba, Saskatchewan, Alberta, North Dakota, Minnesota and Ontario. We currently have nearly 13,000 Hen Houses in place to protect hens and eggs from predators and increase duck production. Every year, these structures produce more than 45,000 ducklings.

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How to Build, Install and Maintain Your Hen House

  • Flax straw (1 50-pound square bale usually makes 5-7 tunnels)
  • If flax is not be available in your area, then substitute with the most durable grass or straw you can find. Wheat and barley straw are too light and don’t work well.
  • Use grass hay for nesting material. Delta has had success with brome hay and other grasses. In Minnesota and South Dakota, flax works well for both the exterior and nest material.
  • 8-foot long base pipe (1.5” square tubing)
  • 30-inch long adjustable insert pipe (1” square tubing)
  • 18-inch long cradle support pipe (1” square tubing)
  • 7’x3’ section of welded wire fencing (2” by 1” mesh with 14 gauge wire) – this is double rolled with flax to form the Hen House
  • Wire must be firm to prevent tunnel from bending (i.e., no “chicken wire”)
  • Two 20-inch lengths of ¼” steel rod, bent to form cradle
  • 12 hog rings and 1 bolt or wire-lock pin to attach insert to post

Total cost will vary with location, steel prices and quantity purchased.

  1. Drill two to three equally spaced holes along the 30” insert pipe for height adjustment. Then drill one hole in base pipe about 8” from the end.
  2. Weld insert pipe to the 18” cradle support pipe, midway along. This will form a T.
  3. Bend ¼” rod pieces into semi-circles. Then weld one at each end of cradle support pipe.
  4. Roll up three feet at one end of 7’x3’ wire fencing and hog ring in 3-4 places to form an inner tunnel.
  5. Spread approximately 2” of flax straw (or equivalent) on remaining 4’ of fencing, then continue to roll tightly. Hog ring end of fencing to complete the Hen House, providing an 11-12” diameter opening on each end. Try not to exceed 12” as Canada geese may use larger Hen Houses.
  1. Where ice is present, drill hole with auger in desired location.
  2. Pound post into wetland bottom, making sure post is not easily dislodged.
  3. Slide insert pipe into base and adjust height so that bottom is at least 3 feet above ice or water level.
  4. Place tunnel in cradle and attach with galvanized wire or hog rings (plastic tie straps eventually break so they are not recommended).
  5. Adjust grass inside Hen House so that it is one-half to two-thirds full, but you should still be able to see through tunnel. Nest material will settle over time, so it is better to have too much than too little.
  6. Record GPS location (if available).
  1. Revisit every year a month or two prior to the nesting season.
  2. Check for and record nesting activity from the previous year. Look for a nest bowl with down, egg fragments, egg membranes, or whole eggs.
  3. Repair exterior by replacing missing flax straw. Hens often remove straw and add to nest bowl.
  4. Remove old nest remains and add new grass to the inside of the tunnel. Make sure Hen House is one-half to two-thirds full of grass.

Click here to download Delta’s Hen House best management practices. These provide our recommendations for the number of Hen Houses per wetland and other suggestions for good installation locations.

How to build a wood duck box

The wood duck, or “woodie,” is popular among North American waterfowl hunters and for good reason. Not only are they one of the world’s most beautiful ducks, but they’re considered among the tastiest. Perhaps the wood duck’s most valuable attribute to hunters is their distribution. Wood ducks nest throughout much of the U.S. and provide good waterfowl hunting opportunities where other duck species are uncommon. In fact, more wood ducks are harvested in the Atlantic Flyway than any other duck species! Across all flyways, wood ducks rank among the top five species in total harvest over the last 15 years.

Though wood ducks are one of our most common waterfowl species today, conservationists once believed they were on the verge of extinction. In the late 1800s, waterfowl hunting was unregulated, and wood ducks were harvested year-round in some areas. In addition, critical feeding and nesting habitat for woodies have been disappearing. Wood ducks utilize natural tree cavities for nest sites. As older forests disappeared, so did available locations for nests. As a result, the wood duck population plummeted, and wood ducks were considered rare in many parts of North America. By 1916, hunting of wood ducks was prohibited in 22 states. By 1918 wood duck hunting was closed nationwide with the passing of the Migratory Bird Treaty Act. The wood duck season remained closed for over 20 years (1918 – 1941).

A True Success Story

The comeback of the wood duck is a true conservation success story. While harvest restrictions and improved habitat were critical to their recovery, a creative artificial nest cavity, or wood duck box, was also important. In 1937, the U.S. Biological Survey tested the first wood duck boxes in Illinois. Wood ducks proved to be very adaptable, and over 50% of the boxes were used the first year. The success of those first 486 boxes prompted the proliferation of wood duck boxes throughout North America. Nearly 75 years later, it’s estimated that wood duck boxes produce 100,000 – 150,000 additional wood ducks each year.

The wood duck or “woodie” is very popular amongst North American waterfowl hunters and for good reason. There are many safe and effective wood duck box designs available to conservation enthusiasts. We recommend wooden boxes because they are less prone to extreme heat build-up that could endanger a hen or her eggs. This is especially important for folks in the southern U.S., where temperatures regularly exceed 90° F during the nesting season.

The cedar box, designed by Minnesota wood duck expert Don “The Duckman” Helmeke, has been found productive and safe for wood ducks throughout North America. While you can use just about any type of wood to build your nest boxes, cedar and cypress are more weather-resistant and will last longer. We also recommend installing a predator guard on each wood duck box post. Boxes are more beneficial to wood duck populations if they improve nest success over natural cavities. Cone-style predator guards are effective at reducing mammalian predation, especially when you install your boxes on land. Here are some instructions for building and installing a cone-style predator guard.

A step by step instruction of adding a predator guard to a wood box.

Here are a few wood duck box basics when choosing a location for your wood duck box(es). First, there must be adequate wetland habitat nearby for the hen and her ducklings. Though wood ducks may nest a mile or more from water, ducklings are more likely to survive if overland travel is minimized. Also make sure there are clear flight lines to the box opening and an easy path to the water. If you’re installing multiple boxes, try not to install them within sight of another box.

Perhaps most important is selecting a site that can be easily accessed for annual maintenance. Regular maintenance (i.e., cleaning out and replacing wood chips) is critical if you want to ensure that your wood duck boxes are consistently productive. Boxes that are difficult for ducks to access are likely to become neglected. We recommend performing maintenance in late winter, just before wood ducks begin searching for nest sites. This date changes with latitude, as boxes in the southern U.S. should be maintained by late January. In northern states, the first wood ducks usually return around mid-March.

Once you find the right location, a wood duck box can be mounted on a variety of surfaces, including trees, posts, and the side of your house or barn. Though it seems natural to install them on trees, the safest location is on a wood or steel post with a cone-style predator guard.