1.injection site free of lumps 

Greater chance of appearing cold season. The main reason is oil seepage before injection without pre-heating. After injection easily lead to local capillary contraction. A long time, local necrosis, inflammation, vaccines are wrapped to form a free mass. This situation vaccine malabsorption. Does not produce a good immune response. So before the cold season injectable vaccine to pre-warm the oil. Need to reach about 20 ~ 30 ℃. 

2 swollen head, swollen face 

When injected oil seepage at the injection site is too close to the head or the head towards the direction of the needle. Often caused by head and facial swelling. In severe cases, such as the owl-like. Cut parts of a cheese-like material swelling and granuloma. Flocks spirit is better, feed, water slightly decreased, no death. - Like 5-7 days to restore. After severe to recover for 2 weeks. 

3 hard-neck 

The oil injection Miao Miao oil injected into the neck muscles. Can cause neck swelling, thicker. Chickens foraging performance drop, eyes closed, necking, yellow-green discharge Xifen, gradual weight loss and death. Because less neck muscles, nerves and blood vessels more abundant. Oil seeps injected into the neck muscle. Easily lead to nerve and vascular necrosis, it will cause hard neck. 

Subcutaneous injection method is correct: a person hold the chicken. Another person in charge injection. When injected with the thumb and forefinger of the chicken neck (near the wings at) skin pinch the skin and neck muscles after separation. Syringe needle toward the back direction. In less than a 30 degree angle to the subcutaneous injection between the thumb and forefinger. After injection of oil seedlings should be distributed between the neck muscles and skin. 

4 injection site swelling, erosion 

Performance of the injection site swelling, inflammation, necrosis, cut seen with granuloma, cheese thereof. Chickens showed lack of energy, decreased feed intake, easy to secondary E. coli, Mycoplasma and other diseases. Antibody levels can not achieve the desired results. 

The main causes of morbidity are: poor health flocks, bacterial infection after injection. Lower general morbidity. 

5 acute death 

Chest intramuscular injection needle is too long or too deep. Pierce the liver leads to liver bleeding. Or at the inside of the leg pierced the aorta vascular injection. When pectoral muscle injection, the needle should be used short 7-9. Needle and injection site into a 30-degree angle. At the upper third of the chest. Piercing the chest toward the back of the direction, not the vertical piercing. In order to avoid piercing the chest and damage internal organs officer. 

6 After laying hens caused decreased immune 

Laying immune decline caused by oil seepage majority and poor health in chickens, chicken catch the action too rude, improper vaccination selected time and other factors. Because high-yield laying chickens more concentrated in the morning. The number of eggs produced in the morning and total days above 80% of eggs produced. The afternoon sheds light dark. Fried chicken is not easy to create the group. Therefore, the choice is 4:00 in the afternoon, especially after the injection of oil seepage is very necessary.