Sudden egg drop is a nightmare to any egg producer because one rarely goes back to the original production. Three weeks ago, I visited a layer chicken farm in Kiambu. The birds had suddenly dropped production. The feed provided was said to be from the same manufacturer.
Joyce, the farm owner, always keeps a close watch on the flocks. She has managed to control many of the very serious chicken diseases through structured and scheduled vaccination.
When I arrived, Joyce explained that over a period of two weeks, the birds had heavily reduced the number of eggs laid. We measure the egg production by percentage of birds laying in the flock daily.
On a good farm, birds lay over a period of 12 months. They start at about 18 to 22 weeks of age depending on the breed of chicken and the season. The production rises sharply to a peak of about 90 per cent in the sixth to eighth week from the date they started laying.
Egg production then declines to about 65 per cent after laying for 12 months. This level is determined to be the unprofitable production and the birds are replaced. The hardest hit lot of Joyce’s birds were laying at 40 per cent.
Yet these were birds which had been at 90 per cent two weeks earlier. It was a great loss. There were two lots with over 90 per cent but another two were at below 70 per cent and dropping.
Joyce explained her birds had several problems. Many of the birds in the lots dropping production snored at night from about 7pm. I confirmed it was not snoring. The condition is called moist rales. These are snoring-like respiratory sounds. They indicate infection of the respiratory tract resulting in production of mucous.
When the disease is not very serious, the problem of rales will occur at night when the temperature drops and the chicken are resting. Long-standing rales are mainly caused by infection with the mycoplasma bacteria that cause chronic respiratory disease in chicken. There was a very high occurrence of minute eggs, soft shelled eggs and eggs with unusual shapes. There were also eggs without shells or some with rough or ridged surfaces.
All the birds had normal appetite and they looked happy and alert. I could, however, see many of them were underweight.
The birds generally had normal droppings but there were signs of impeding coccidiosis since some of the birds had a taint of chocolate brown content in the droppings. The youngest lot that was yet to lay had a high level of coccidiosis.
I opened six of the unusual eggs and confirmed indications of bacterial infection. Some eggs had cotton-like clusters while others had excessive blood supply.
Finally, I reviewed a laboratory feed analysis report. It showed a number of the critical feed ingredients were either lower than the standard or in excess of the standard. Excess levels may sound good but unfortunately some components in excess may be toxic, prevent proper utilisation of other nutrients or cause the birds to have increased fat deposits that interfere with production.
At the end of the investigation, I diagnosed substandard feed, coccidiosis and mycoplasma infection. The feed was also below standard. I advised Joyce to take several measures. She would take up the feed issue with the manufacturer to be given feed of the correct standard on all nutritional parameters.
Joyce would take one live bird with rales to the Veterinary Research Laboratories for post-mortem and identification of the infectious agent or agents in the eggs and the birds’ respiratory system.
While awaiting the laboratory results, Joyce would treat the birds for coccidiosis and mycoplasma infection. The bird taken to the laboratory should not be treated at all. All the birds with rales would be treated with a drug specific for mycoplasma bacteria. I gave Joyce the prescription.
The first results from the laboratory were quite interesting. The bird had an excess of round worms called ascarids in the intestines.
This explained the high feed intake in the birds. Ascrids compete with the host bird for food in the intestines. They simply steal the food after the bird has digested and is ready to absorb it into its body. This partly explained the low body weight of Joyce’s layers despite them having good appetite.
The diagnosis of ascarids was rather surprising considering all the birds are on a cage system. The most likely source of the warms would be drinking water. We agreed with Joyce that was an area for further investigation. In the meantime, she would treat all the birds for worms every two months instead of three.
We are still waiting for the bacterial analysis report. Mycoplasma bacteria take long to grow in the laboratory unlike most other bacteria.
Two weeks from the visit, Joyce reported the rales in the birds had stopped and the eggs were getting back to normal. The laying percentage had risen close to normal.