Trapnests for Improvement Breeding
The following is the original (expanded) version of my article “Improve Your Flock with Trapnests”, published in the April/May 2017 issue of Mother Earth News. It was added to the site in March of 2018.
In “Breeding Our Own Chickens” I discuss why the mass-market hatcheries are not the best source for robust, productive chicken stock for the homestead and small farm; and explain that a “breed your own” project is well within the reach of what I call the “ambitious” homesteader, and certainly of any small farmer serious about breed improvement. And “Making and Using Trap Nests” describes the design and step-by-step construction of the trapnests I’ve used here for many years.
This article argues that nest-trapping is an indispensable selection tool in any serious improvement breeding project, and offers much more detailed information about its use. It describes as well two other trapnest designs you might consider.
While nest-trapping could be used by the home flockster or the small farmer as a test for determining “who’s laying and who’s lying”, there are other, less labor-intensive ways for judging relative productivity in laying hens for utilitarian and economic purposes. An excellent guide, free from The Livestock Conservancy, is “Selecting for Egg Production”. Hands-on inspection, for soft, enlarged combs and wattles; wide, moist vents; generous space between pelvic bones, and between pelvic arch and keel; and expansive, soft, pliable abdomens, reveals hens most likely to be the outstanding layers in the flock.
For purposes of selection in breeding, however, there are many egg-production traits we simply cannot know without determining precisely which hen is laying which egg. Yes, those hens with the “wide, moist vents” are the ones in active production. But is a given “moist, wide” hen laying five eggs per week, or six? With an average weight of 57 grams, or 64? Knowing those answers with certainty is essential if we are selecting layers as breeders, that is, laying hens whose daughters will lay even more eggs of larger size. Targeting other egg traits might be important as well, for example, intensity of shell color in breeds known for unusual colors such as Ameraucana, Marans, and Welsummer. And what about egg shape? or shell texture, thickness, and integrity (absence of flaws that weaken the shell)? Like rate of lay and average size, such eggshell qualities are heritable, so breeding for production of more-desirable eggs in future years requires removing the layers of less-desirable eggs from our breeding program now. And that requires trapping the hen in the nest with the egg she has laid, so we can identify her and mark her egg for our records before releasing her.
The decline in serious poultry breeding at the smaller end of the scale has brought a dearth of information about nest-trapping in the contemporary literature. Diligent online searches, however, yield a few trapnest designs from the older farming and homesteading literature. (See this compendium of some older designs, familiarity with those designs will help you choose a model which best fits your management style, henhouse layout, and skill set. Be warned that some of these designs are difficult to figure out and the graphics are obscure. But careful study reveals the core concepts, which with a bit of ingenuity can be adapted to fit your own preferred design.)
Many designs are possible, with two core requirements: (1) a door in the entrance which allows the hen to enter the nest when in the “set” position but that (2) is triggered to drop or swing into blocking position by the movement of the hen into the nest. Some designs are rather complicated, such as the “treadle” type featuring a platform on a pivot between the entrance and the nest itself: When the hen steps onto the platform, its tilt on the pivot triggers the swing of the treadle to block the doorway. Such complicated designs require much greater interior depth to accommodate the treadle. Since I like to mount my nestboxes on the wall, units requiring something like 24-inch depth are out of the question.
The most essential requirement of the design is that it work, one hundred percent of the time. Data from nest-trapping helps determine literally which hens become the foundation of your stock through all future generations, and which go to the stewpot. Each failure of your trapnests to capture a laying hen results in unidentified eggs, undercutting the specificity needed to make those informed decisions.
The following is a brief description of trapnests I have used here, for the purpose of illustrating the essential design elements and the potential problems to avoid.
Purchased Trapnest Fronts
The only option I know for buying a trapnest front is made from heavy gauge wire, available in two sizes from several poultry suppliers. Comparison-shop for reasonable prices, which vary a good deal for exactly the same hardware. Oddly enough, the smaller size is the more expensive; and I found shipping costs to vary astoundingly from one supplier to another: The same order, six of the larger fronts, carried a $132 shipping charge from one supplier, only $19 from another, both of them in Florida! Note that, apart from cost, the larger front may be the better choice even if you’re breeding a smaller breed. After all, you may someday want to work with a larger breed; and it is easy to modify the nestbox in a way that forces a small hen entering the nest to make solid contact with the larger door in the “set” position to trigger its release.
This wire nest front is actually designed to fit onto purchased sheet-metal nest units. I avoid such units, the only ones I ever used were pretty junky, and since I scrapped them long ago I’ve preferred my sturdier homemade versions. However, following the lead of breeders who have mounted the purchased wire fronts onto their homemade trapnests, I made a set of four of my own. I cannot recommend them.
The problem is the amount of force the hen has to exert on the door, folded into the “set” position, to trigger release. Numerous times I watched as my hens entered the nest, brushing the edge of the wire door but failing to trigger release. I added wood strips, reducing the distance between the wire and the edge of the nest and requiring more forceful contact by the hen as she squeezes through, and managed a capture rate of about 50 percent. That’s not nearly good enough.
Perhaps I could continue to modify the doorway to ensure release, and you could well have better luck with larger hens. (My hens are all Icelandics, definitely on the small side.) But I have abandoned the commercial trapnest in favor of less “fiddly” versions made and fine-tuned here at home. If you are choosing between these options, keep this in mind as well: The expense of building your trapnest will be the same in either case. Then you can either spend $21 to $39 per wire front for each nest, or get your doors essentially for free (using scraps of plywood leftover from the project).
Variations on the Swinging-Door Design
For simplicity, it would be hard to beat the two designs in Gail Damerow’s A Guide to Raising Chickens (pages 172-73). I have made and tested several variations, with modifications of my own.
The basic design features a door which is suspended over the entrance to the nest, supported in this “set” position by a prop stick from below, an overhead wire bent at its end into a short hook, or any number of other ingeniously-rigged options. Unlike the purchased wire fronts that require a significant push from the hen, the door’s support can be set to “hair trigger”, the merest nudge from the hen’s back as she enters the nest knocks it off its prop, releasing it to swing into blocking position behind her.
This design’s advantage is that it is easy to build. The biggest challenge is spacing the suspended door at just the right distance over the edge of the nest to ensure easy and inviting access while ensuring that the hen cannot enter without making contact. The precise sizing of the opening may require experimentation and modifications for your specific design, and even for the average size of the hens you are trapping.
I have made three modifications to Damerow’s basic design. Since the door swings to the inside to be set, obviously greater nest depth is required to ensure the hen is deep into the nest space (i.e. the capture space) before the door drops. But as noted, too much nest depth results in unwieldy nestbox units difficult to mount on the wall. To reduce nest depth needed, I cut the door in two and hinge the resulting halves. Now the required radius for the door’s swing is reduced by half and much less overall depth is needed for the trapnest. The swinging-door units I’ve made are 16 inches deep, only a few inches deeper than the typical 12-inch depth.
I don’t want the hen settling down in the nest too close to the entrance, if she does, she may trigger release of the door before she’s deep enough inside to be trapped. Getting “booted” from the nest by a prematurely released door may make her shy of entering the nest in the future.
My solution is to add a strip a few inches past the entrance to retain the nesting material and define the nesting space deeper inside. The resulting empty “vestibule” discourages settling-in near the entrance and draws her deeper into the nest before the door is triggered.
As said, this design depends on hair-trigger release of the door. If the hen has to fly up to a wall-mounted nest, her forceful landing in the entrance, wings a-flutter, could trigger premature release. It is important to provide a perch she can land on first, ensuring her entrance into the nest itself is more sedate.
My “Granddaddy’s Rabbit Box” Design
When I asked my father to help build my first trapnests, he suggested basing the design on the “rabbit boxes” his father used to trap wild rabbits, featuring a baited “trigger stick” as the release for a sliding door suspended over the entrance. In my version there’s no bait on the trigger, of course, but the hen knocks it loose as she settles into the nest for laying, releasing the door. (Step-by-step construction is discussed and profusely illustrated in “Making and Using Trap Nests” and in Appendix A of my book The Small-Scale Poultry Flock.)
This design, and others featuring a door that drops, in the same plane as the doorway, does not require additional nest depth. But I prefer to add a few extra inches to create an empty “vestibule” as described above to tempt the hen deep into the capture space. Note that the door is suspended securely in the open position by its weight, pulling against the notch in the trigger stick at the string’s other end. It drops only when the hen’s settling-in ritual knocks the stick’s notch loose.
This design is more complicated to build because of the tracking strips required to guide the door’s drop. But it is the only design I’ve found to be one hundred percent effective, it always traps the hen if properly set up. It cannot be otherwise, given that the hen is fully in the capture space (not just in the process of entering it as in the swinging-door design) before the door is triggered, and that failure to knock the trigger stick free as she settles in is simply not possible.
Note that routing the string between door and trigger stick through an overhead hook works for me because of a conveniently positioned henhouse framing piece. I have no doubt that ingenious flocksters lacking that convenience can come up with other means for triggering the door’s drop, perhaps running the string through a hook screwed into the wall above the back of the unit.
Additional Design Thoughts
- Hens may be frightened if the door slams shut too loudly or jarringly. Damp the force of the impact with some sort of “bumper”. Scraps of discarded inner tube stapled in place work fine.
- Make sure there is plenty of ventilation in the sides, bottom, and tops of trapnests. A hen trapped a quarter hour in summer will appreciate good airflow.
- Design doors that are easy to install and remove for storage, since the trapnests will be used as ordinary nestboxes most of the year.
Nest-trapping is not something to do all the time, that would be wildly impractical, given the intensity of monitoring required. Instead, schedule a period of several days at a strategic point in the laying cycle. When you decide to nest-trap will vary depending on the information you’re trying to capture. Trapping in summer would track egg production at its peak, while trapping in fall could give precise dates for onset of lay for individual pullets. You would nest-trap in winter, obviously, if you’re selecting hens who better hold production in the winter. Nest-trapping as part of the final selection of hens as breeders should be routine. Trapping in late winter/early spring identifies which hens lay best in those shorter days, likely to be the best layers the rest of the year.
Set aside a period for nest-trapping when you will be able to check the nests frequently, as often as every quarter hour in the hours when hens are most likely to lay. And be sure to have enough trapnests in proportion to the number of layers you are testing, something like one trapnest for every six hens. The integrity of the data generated depends on trapping every hen who lays an egg until you can make a record, if urgent hens blocked from the nests lay in the litter, there goes an irreplaceable swath of your selection data.
Avoid nest-trapping to track production levels during the molt. Because the hen is putting so much of her resources into replacing feathers, and individual hens molt on different schedules, laying data during this period (typically early or mid-fall through early winter) are not valid.
How many days at a time should be devoted to trapping? More than one or two, certainly, enough to be sure of going through a couple of full cycles of even the least productive hen. Remember that even the best-laying hen has a periodic “reset” day when she lays no egg. If her off day falls within the test period, she will show as less productive than a hen whose reset happens not to occur in those days, even if the average production of the two is the same. The best strategy is therefore to average out your results by scheduling two or more tests in the overall testing period, say four or five days each and three weeks apart.
Since nest-trapping requires this serious commitment of time during the testing periods, it could be seen as a drag on efficiency. But actually nest-trapping can increase overall efficiency. Imagine you have 25 hens in your breeding program. You don’t nest-trap, but it’s obvious that one hen lays a chronically small egg; one, lopsided eggs; and three others, eggs with shells that are thin or have wrinkles or fracture lines or unsightly calcium bumps. Knowing these traits are heritable, you always discard these eggs when selecting for incubation. Problem solved regarding selection against these undesirable traits, but . . . How many breeding hens do you have again? Twenty-five? I don’t think so: You have twenty, plus five freeloaders on your breeding program! Why not use a set of trapnests to eliminate those freeloaders and boost efficiency?
The usefulness of your nest-trapping data depends on careful record keeping. That depends first of all on having positive identification of each hen. The two methods I’ve found best for permanent identification are plastic bandettes and metal wing bands, each available in various colors and sequentially numbered lots.
Check her identification before releasing the trapped hen, and mark her egg (using a pencil, not a marker pen) with her ID and the date. Now you have the basic information that will guide selection for egg traits. Your specific use of the raw data depends of course on the characteristics you want to target. How you use your trapping data will differ from how I use mine.
If you are comfortable with digital spreadsheets, set one up to automate the analysis of your data. Your spreadsheet might enable weighting of entries for each of the targeted characteristics mentioned above, with positive scores assigned for frequency of lay and size of egg, and negative scores for shell flaws or undesirable shape or color. Enter formulas for automatically calculating overall scores for each hen.
Customizing the Data
The egg traits above, for level of production and quality and size of egg, are obvious targets for selection in an improvement breeding project. During five years of breeding here, I have aggressively targeted the sorts of eggshell and shape flaws discussed above, lopsided, bulges, fracture lines, and the like, and as well eggs that are too round or too evenly oval (obscuring the location of the air cell, important to know when saving eggs for hatching). Already, I have come close to eradicating these flaws. But the sophistication with which you can target many other selection criteria will be guided by your other breeding goals, and limited only by your ingenuity.
For example, modern poultry breeding has ignored the question of longevity, to say nothing of production in relation to advancing age of a laying hen. But suppose you want to breed for greater longevity (genetically related to greater vigor, health, and hardiness, by the way) while keeping a higher level of productivity as hens age? Nest-trapping to the rescue: If Hen 106 and Hen 141 trap at the same level of production but the former is a year older than the latter, who is the obvious candidate for breeder?
I have found that, though all my hens are eating exactly the same, yolk color varies a good deal in the eggs. I nest-trap to identify hens that consistently lay eggs with pale yolks, in contrast to hens whose rich orange-yellow yolks are a joy to see beside my breakfast bacon. Guess whose daughters I want as my future layers.
If you, like me, prefer to hatch with natural mothers (“broody” hens), remember that you have to make broodiness a selection trait to ensure keeping it in your flock. I keep extensive records about the performance of my flock’s “working mothers”. Nest-trapping allows me to select and hatch eggs from known broodies in order to ensure the trait remains strong in at least a portion of their daughters.
Indeed, while we’ve focused above on issues related in some way to rate and quality of eggs laid, any trait we consider worth enhancing in our flock, a real “go-getter” approach to foraging, say, can be more precisely targeted by nest-trapping to ensure hatching from eggs of hens we’ve found to be superior.
Remember that, while the cock doesn’t lay eggs, he carries the genes of his mother for traits you are targeting. So choice of a breeding cock can boost future performance of hens, if nest-trapping has proved his mother has the traits you’re looking for.
In conclusion: There is no other method that comes close to the specificity and breadth of selection data available through nest-trapping. If you’re serious about breeding, you really should be using this tool!