The chicken “orchestra” was in full performance when I arrived on the farm in Ruiru last week.
The layer birds appeared really happy with their situation. The harmony of their voices could have embarrassed some musical groups.
The birds confirmed the owner’s report that they were generally happy but one batch had a serious problem that had lasted about 35 days, surprisingly with very low mortality.
Bonnie, the farm manager, quickly briefed my colleague, Dr Joyce, and I on the problem. The farm had about 8,000 layer chickens of the Isa Brown breed in five different stages of production.
Two batches were in peak production, laying at about 75 and 80 per cent. The third batch, called S9 on the farm, was supposed to be hitting peak production of about 85-90 per cent at 22 weeks of age, but was currently only doing a measly 20 per cent.
The adult birds were raised on the cage system with three to four birds per cage, as recommended.
Dr Joyce asked Bonnie to give us the full brief and we would conclude by thoroughly interrogating the problem with S9. The fourth batch comprised spent layers that were to be sold for meat within the week.
Finally, there was the fifth batch of grower chickens about 10 weeks old in a house detached from that of the adult birds.
These birds had a bit of brown stool and Bonnie informed us he had already started treating them for coccidiosis. He provided us with clean protective clothing from his stock including caps, dust coats, gumboots and latex gloves.
Chicken and pig farmers should always ensure that they have the protective clothing for visitors and their veterinary service providers.
It is part of the best practice in biosecurity procedures that ensure the visitors do not introduce diseases on the farm or transfer diseases to others.
START TREATMENT EARLY
I informed Bonnie we would first examine the growing batch from outside their house then observe the two batches in top production from inside their housing units before going into the problematic lot. We would not check the spent birds.
My suggested pattern aimed to minimise cross-contamination of the houses and chances of disease transfer between the different lots of birds.
The growing birds all appeared normal in demeanour, activity and body condition. There were only a few brown-coloured droppings and Bonnie confirmed the number of birds affected by coccidiosis had greatly reduced since he started treatment.
I reiterated to him it is always advisable to start treatment early on noticing the brown colour to maximise effectiveness of treatment and prevent mortality.
All the laying birds were housed in one large building segmented into individual units by stone walls, mesh wire and plastic sheeting.
Each unit had a separate entrance with a disinfectant bath on the outside. We waded through the disinfectant and examined the birds in the two top laying batches.
I noticed a few birds were recovering from infectious coryza and the manager confirmed treatment for the disease had been completed with good response.
I explained to Bonnie the attack by the disease could have been the cause of the drop in peak egg production. The birds would possibly further increase production once they all fully recovered.
At last, we got into the problematic S9 lot of layers. The birds generally looked happy. They had very good appetite, were active and looked bright, but there was a huge problem. The environmental sound in the house felt like heavy water jets repeatedly hitting a hard surface.
The floor was completely wet and in some areas water flowed from the sparse normal chicken droppings seen on the floor.
“Doctor, it is amazing these birds appear to be urinating and this has been happening for the last 35 days despite various treatments,” Bonnie said.
I could see that the birds kept squatting and squirting almost clear fluid from their vents. The vents were all clear and once a bird completed the act and reverted to normal posture, one would not identify it. This is unlike birds with regular diarrhoea where the vent feathers are matted with soft or fluid droppings.
Bonnie explained the affected 1,800 birds had come from one supplier, separate from the other batches at 15 weeks of age. They had shown some diarrhoea a week after arrival, which then progressed to the current watery discharge. Treatment with antibiotics, electrolytes and probiotics had failed to resolve the problem.
Some birds were sacrificed for postmortem but no definitive diagnosis was made. The birds were eating the same feed as the other layers. Bonnie further said the death rate was very low at about one bird every two weeks.
The unit had three sets of cage batteries named S9A, B and C. Birds in A and B were the most affected but the problem was progressing to C.
There was almost no egg production in battery S9A. Total production in this lot was about 20 per cent and dropping. I estimated that about 80 per cent of the birds in the unit were affected by the watery diarrhoea.
Upon examining the birds, we found the majority were grossly underweight. When we held them upside down, they discharged clear mucoid fluid through the mouth. I attributed that to the large amount of water they were drinking to replace the one lost in the diarrhoea.
This was definitely a challenging occurrence that defied the diseases documented in layers. I contacted professional colleagues at the Veterinary Research Laboratories at Kabete and we took samples for laboratory investigation. We are awaiting the results.
In the meantime, I put the birds on a strong broad-spectrum antibiotic for five days and continuous administration of electrolyte and vitamins in water. I also advised Bonnie to treat the drinking water with chlorine.
Further, he would administer a suitable yeast fermentation metabolite in their feed. I am eagerly awaiting the laboratory results and will share them when they are out.