Yolk Sac Infection

Let's start with a principle - "The total mortality rate in a batch of chickens is proportional to the mortality rate in the first week."

Assume there are 1,000 chickens in a batch over 40 days. If the mortality rate in the first week is 10, then by the end of 40 days, the number of dead chickens will be 60; if it is 5 in the first week, then it will be 30 by the end of 40 days. Therefore, the first week is very crucial for poultry farming, as it sets the performance for the remaining period. In an ideal farm, the mortality rate is kept below 1% in the first week. Moreover, if brooding is not done properly in the first week, variations in size among the chickens can occur later, which negatively impacts the poultry business. However, with proper management in a farm, it is possible to achieve an additional 5 grams of weight in the first week, which translates to an extra 35 grams by the 35th day without any additional feed, purely through proper management.

Now, yolk sac infection is largely responsible for the mortality rate of chicken chicks in the first week. If this infection can be prevented, it is assumed that the performance of the entire batch will improve.

The relationship of Yolk Sac Infection with the Yolk.

Among the various stages of hatching a chick from an egg, on the 19th day, it is observed that the yolk enters the chick’s body. The pathway through which the yolk enters the body is called the navel. Now, the question arises why the yolk enters the body through the navel. Essentially, right after the chick hatches from the egg, it needs energy to be able to run after the mother hen, which is a natural rule. This energy is obtained from the yolk, and the nutrients within the yolk allow the chick to survive up to 48 hours without any food or water. However, this yolk also plays a significant role in facilitating bacterial growth within the body.

The process of infection

Condition of the Navel

Yolk sac infection can occur in many ways, but most often it is seen in hatcheries where the eggs set for hatching are not properly cleaned or are hatched in a contaminated state with feces. During hatching, the chicks become infected with bacteria. After these chicks reach the farmers, the mortality rate begins a few days later. In such cases, there is little the farmers can do, so it is advisable to source Grade A chicks from reliable and high-quality hatcheries. Furthermore, even after acquiring high-quality chicks, infections can occur if the farmers do not maintain ideal brooding conditions, due to contaminated litter and excessive humidity, allowing bacteria to enter the body through the navel.

Stress

When chicks are transported from the hatchery to the farm, they experience stress due to transportation. If the chicks are not properly transferred to the farm, they may die due to stress-related causes. Often, in a rush, chicks are hastily dumped from the box into the brooder, which can cause injuries leading to ruptures in the navel, resulting in infections. Therefore, before releasing the chicks into the brooder, the light in the brooder should be dimmed and the chicks should be released slowly, gradually increasing the temperature.

Dehydration

During transportation from the hatchery to the farm, it is not possible to provide water to the chicks, resulting in dehydration. Therefore, upon arrival at the farm, it is essential to first give the chicks clean water, ideally with added electrolytes and glucose for better recovery. Often, farmers mix jaggery in the water; while jaggery serves as a good energy source, excessive amounts can actually aid in the growth of bacteria in the yolk sac.

Prevent

To prevent yolk sac infection, certain methods must be adopted.

• Firstly, you need to source Grade A chicks from reliable and high-quality hatcheries. Often, we purchase Grade B chicks due to their lower price, but no matter what we do, the mortality rate of Grade B chicks will be higher compared to Grade A.

• Properly set up the brooder, ensuring everything necessary for an ideal brooder is arranged.

• The brooder must be pre-heated to the required temperature before the chicks arrive.

• Before releasing the chicks into the brooder, ensure that there is soft lighting; intense light increases stress levels in chicks.

• Line the floor of the brooder with paper and maintain it for 5 to 7 days. Ensure the paper does not get wet; replace it if it does. Change the paper every 3 days.

• There must be good ventilation in the brooder.

• After the chicks arrive, provide water and mix in the following:

- Multi-Vitamins - 1 gm/5 liters of drinking water for 5 days

-Enrofloxacin INN 10%(Generic Name) - 1 gm/5 liters of drinking water for 5 days

Although it is generally advisable to avoid antibiotics, given the climate and environmental conditions in our country, administering a mild dose of antibiotics can reduce early mortality in chicks.