Storey's Guide to Raising Chickens (76 page)

Between hatches and at the end of every hatching season, thoroughly clean out the incubator or hatcher. When no eggs are in the incubator, unplug the unit, remove and clean all removable parts, vacuum up loose fluff, sponge out hatching debris, and scrub the incubator with detergent and hot water. Take care not to wet down or spray the heater or any electrical parts — instead brush
them off with a soft-bristle paintbrush and move the vacuum hose over them gently to pick up the loosened fluff.

When the incubator and all its parts look thoroughly clean, wipe or spray the nonelectrical parts with a disinfectant such as Germex, Tek-Trol, Oxine, Vanodine, or chlorine bleach (¼ cup bleach per gallon of hot water; 15 mL/L). Leave the incubator open until it is thoroughly dry, preferably in sunlight, then store it in a clean place.

If mice, paper wasps, or mud daubers have access to your incubator storage area, prevent them from setting up housekeeping in the incubator by plugging vents or covering them with duct tape; remember to unseal the vents next time you operate the incubator. I fastened pieces of window screening over the vents of my cabinet incubator; the screens keep out critters during storage and don’t impede airflow during incubation.

To monitor the progress of each hatch so you can remove spoiled and nondeveloping eggs, you’ll need a candling device. A handheld candler looks like a small flashlight with a plug-in cord. In fact, a small flashlight works at least as well as, if not better than, the appliance designed for the job.

So before you go out and spend money on a candling device, look for something around the house that might work equally well. All you need is bright light that comes through an opening smaller than the diameter of the eggs you want to candle. If you have a flashlight that is too big, cut a hole in a piece of cardboard and place it over the business end of the flashlight, or tape a short piece of empty toilet-paper or paper-towel tube on the end, so only the light comes through the narrowed opening.

Use your candling device in a dark room. Hold the egg at a slight angle, large end to the light and pointed end downward. Making sure your fingers don’t block the light, turn the egg until either you see something or you’re certain there’s nothing to see.

White-shelled eggs are easier to candle than eggs with colored shells, which is why white eggs have become the industry standard. Similarly, plain-shelled eggs are easier to candle than eggs with spotted shells. A good way to gain practice candling is to hatch white-shelled eggs in your first setting. But don’t buy white eggs from the grocery; they’re not fertile, but even if they were, they wouldn’t hatch well because they have been refrigerated.

Examine eggs after 1 week of incubation. You will likely find one of three things inside the shell:

After 1 week of incubation, a properly developing embryo (top) appears as a web of vessels surrounding a dark spot. A thin, irregular ring around the shell’s short circumference (bottom) means the embryo has died.

A web of vessels surrounding a dark spot — the embryo is developing properly

A thin ring within the egg or around the short circumference — the embryo has died

Nothing (or a vague yolk shadow) — either the egg is infertile or the embryo has died

Assuming you remove infertile eggs and those with blood rings during the first candling, examine the incubating eggs again after 2 weeks. You will likely find one of two things:

A dark shadow except in the air cell at the large end (you may see movement against the air-cell membrane) — the embryo is developing properly

Murky or muddled contents that move freely and/or a jagged-edged air cell — the embryo has died

The majority of embryos that die do so at two peaks. The first embryo death loss occurs within a few days of the beginning of incubation. The second, larger death loss occurs just before the hatch. The most common cause of embryo deaths clustered during early incubation is improper egg handling or storage. Embryo deaths during mid- and late incubation may result from an inadequate breeder-flock diet.

Embryos that grow to term but fail to hatch may be a result of bacterial contamination: in other words, unclean eggs were placed in the incubator. The multiplication of bacteria within a contaminated egg may cause the egg to rot and stink. Left in the incubator, a rotting egg may explode, spreading bacteria throughout the incubator and contaminating other eggs.

Any time you open your incubator and smell an unpleasant odor, use your nose to ferret out the offending egg. It may or may not exude darkish fluid that beads on the shell or (due to the pressure of gases within the shell) may be cracked and leaking. By candling on days 7 and 14 and removing nondeveloping eggs, you can avoid the unpleasant experience of a rotten-egg explosion.

The first few times you candle eggs, break open the culls to verify your findings; take the eggs outside, in case the contents smell bad. Even after you gain confidence in your candling abilities, continue breaking and examining culls; you might learn something that will help you improve your future hatching success.

Assuming you incubate only properly stored, clean eggs, the majority of your fertiles should hatch. The average hatching rate for artificial incubation is 75 to 85 percent of all fertile eggs.

To optimize incubator space and improve your overall hatching rate, incubate a full setting for 15 hours, then candle and remove infertile eggs and those with germinal discs (the dark spots) that are smaller than the majority. Put the remaining eggs back into storage, where they will safely go dormant, and repeat the process with a second setting. Combine the best of both settings and incubate as usual. This technique requires a more powerful candling device; the best one I ever used was a slide projector.

A wonderful book that shows photographically all that goes on inside a properly developing egg day by day is
A Chick Hatches
by Joanna Cole and Jerome Wexler. This fine book is out of print but is well worth looking for at your local library, borrowing through interlibrary loan, or searching for in used bookstores or on the Internet.

A normal hatch is complete within 24 hours of the first pip. A dragged-out hatch, or one that occurs earlier or later than expected, may be caused by improper incubation temperature or humidity. Another cause for so-called draggy hatch is storing eggs over a long period of time while collecting enough to fill the incubator — the eggs stored longer will take longer to hatch. Yet another cause is combining eggs of various sizes in one setting. Larger eggs take longer to hatch than smaller eggs, so if you combine eggs from bantams and large fowl, or from light and heavy breeds, the bantam eggs or those from the lighter breeds will usually hatch first.

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