As the duck and goose sectors are fairly small relative to other poultry sectors, there are also relatively few hatcheries that specialize in waterfowl species, and their programs and procedures are largely based on traditions and many years of practical local experience, according to Pas Reform Academy senior hatchery specialist Maciej Kolanczyk.
Usually, people try to mimic Mother Nature in which waterfowl nest close to water, and a brooding female returns to the nest from the water wet and chilled. It would seem that these conditions help hatchability, as it is rare to find an unhatched egg in the nests of wild ducks or geese, Kolanczyk said.
As a result, spraying eggs during incubation became a standard procedure, he noted, pointing out that this begins somewhere between day 10 and 14 and is continued until eggs are transferred. Trolleys must be moved out of the setter; the eggs are sprayed with lukewarm or cold water and then returned to the setter.
In a multistage setter, the effect on the other eggs in the machine is only temporary, Kolanczyk said, but a single-stage machine needs much more time for the settings to be restored.
Generally, two types of trays are in use: plastic trays, where the eggs stand upright, and metal-wire trays where the eggs lie flat or are half-tilted. Some goose hatcheries claim that combining spraying with turning the eggs manually an extra time each day along their long axis also has a positive impact, Kolanczyk reported. However, he said this requires a lot of manual work, which can be a problem as hatcheries are getting bigger and labor costs higher.
Kolanczyk said waterfowl hatcheries are looking for better answers to the fundamental questions: What is the actual effect of the spraying? Does it simply cool the eggs down? Or does it have another function? And is it necessary?
Waterfowl eggs differ physically from chicken eggs. To cope with the humid environment, they have a strong waxy coating — a cuticle — which protects them from infections. However, this “tight packing” impedes the exchange of gases and evaporation of water. Its structure must become open early enough to provide the growing embryo with sufficient oxygen and create an air cell big enough to facilitate hatching, Kolanczyk explained.
He said nature can be overridden by removing the cuticle in advance through washing the eggs with a sodium hypochlorite solution in a specialized washer under strictly controlled conditions.
However, washing makes the “naked” eggs much more vulnerable to infections, Kolanczyk said, noting that hygiene in the hatchery needs to be perfect and should include early removal of “clears” and early deads, absorption of contaminated air at transfer and good control of fluff at hatch. These extra requirements are balanced by the elimination of spraying and make incubation of waterfowl eggs as simple as for chicken eggs.
Another possible option — used by some hatcheries — is a single-stage incubation, where setter inlets, outlets and door are fully sealed for the first 14-17 days, Kolanczyk said. Eggs must be clean, fresh and good quality, but not disinfected. As long the ventilation remains closed, humidity stays at 80% or higher and the carbon dioxide concentration can rise as high as 1%. No spraying is practiced later on, he said. Although not very common, this system leads to surprisingly good hatch results.
According to Kolanczyk, the main problem when incubating waterfowl eggs is controlling cuticle status, which can be gradually destroyed by spraying — creating specific microclimate conditions — or removed by using a chemical wash.
The cooling effect of spraying is most likely not relevant, he said, as chemically washed eggs hatch well without spraying.