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INFERTILE / CLEAR EGGS
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Breeding Challenges
Infertility in birds is the failure of a true pair to produce eggs with viable embryos. It differs from low hatchability where fertile eggs fail to hatch. Egg candling allows you to assess whether low hatchability or infertile eggs are the problem. Poor hatchability and infertility are two different problems with very different solutions. The below information related to infertility (producing "clear" eggs, aka duds) in birds that appear to be actively breeding, yet are unable to produce any young.
Infertile eggs in previously proven breeders
The root of infertility is either (or combination of)
Nutritional:
Inadequate dietary calcium, sodium and energy can interfere directly with egg laying and fertility.
Over-supplementation of zinc can cause infertility.
Obesity causes problems with decreases ovulation especially in Galahs, Budgies, Amazons and Macaws.
Increasing the variety of foods fed can stimulate fertility
Aflatoxins in seed can lower fertility.
Genetics:
Inbreeding can result in lowered semen quality, abnormal mating behavior and physical defects
Some bird species have been breed that they have become physically unable to breed, for example some budgie species
Hybrid eggs have a low hatchability
Physical:
Either too young or too old
Poor physical condition for whatever reason.
Disease: For example, Psittacosis is commonly associated with infertility and the deaths of babies in breeding aviaries. The first step should be a vet visit to eliminate illness as the cause of the problem. The only test that may be needed is a simple white blood cell count. If his count is normal or only slightly elevated, then the infertility problem is more likely to be social or environmental.
Overuse of medications. For example, Doxycycline lists amongst its side effects a lowering of male fertility.
Reproductive disorders: i.e. ovarian cysts or tumors, testicular neoplasia, etc.
Physical impairments (can't properly balance on top of the female to copulate)
Social:
Same-sex birds are paired up. If two females or two males are paired up, they will go through the motions of breeding the same way as they were a compatible pair. Two females will lay eggs and incubate them. Two males will also mate and go through the motions of nesting without any eggs.
Excess time spent in territorial defense against perceived threats or potential rivals can result in lowered fertility. If birds are stressed by human presence then this will limit fertility.
During the breeding season, it is important to limit disturbances, such as visitors, noisy dogs, as well as predators such as cats, birds of prey, rodents and snakes
Environmental:
Extreme temperature variations may cause temporary infertility.
All perches should be firmly fixed. In some instances, the "favored" perch for mating (which could be the top of the nest box) was too close to the ceiling of the aviary or the top of the cage to allow the male to successfully balance on top of the female, thus resulting in infertile eggs; or the perch was not providing a stable enough surface to allow successful copulation
Infertility in birds that were previously fertile:
Nutrition:
If the birds are newly acquired and successfully bred at their previous location, investigating and potentially implementing the same diet they were previously on is the first step.
If the nutrition has NOT changed from when they were still able to successfully produce, then changes in health status or environmental differentials should be considered.
Physical:
Marginal illness in either the male or the female can be the cause of infertility. The first step should be a vet visit to eliminate illness as the cause of the problem. The only test that may be needed is a simple white blood cell count. If his count is normal or only slightly elevated, then the infertility problem is more likely to be social or environmental.
If the female successfully lays eggs, then the problem is more likely with the male.
Environmental:
The male may not be comfortable where he is.
Maybe the highest perch is too close to the ground or the male may not like what he sees from inside his cage / flight.
He may resent the fact that the perches of adjacent flights are higher than in his own.
He may hate his neighbors or he may be intimidated by them if they are larger than him.
Many breeders stack their cages. A pair that used to produce nicely in the top flight may stop producing if moved to a lower level.
Another very common problem may be a cage with a group of immature or unrelated birds within view of your breeding pair. Even though a large percentage of pairs will tolerate this situation - a small percentage will not.
These types of problems can be avoided by arranging your aviaries and placing your perches so that no one is higher than anyone else. Also, try to keep birds of the same size together.
If these situations cannot be rectified, then you may want to consider installing blinds between the cages. |
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