Usually, the time for pigeons to hatch eggs is about 18 days. If the incubation time is more than 18 days, the pigeons are still not hatched, which may be caused by the following reasons:

1. The sperm motility of male pigeons is insufficient, which leads to the failure to hatch normally;

2. Breeding pigeons are weak and may not be able to provide sufficient incubation conditions;

3. Breeding pigeons did not carry out systematic deworming and comprehensive cleaning before pairing, which may affect their hatching;

4. During the incubation process, it was influenced by the external environment, such as cold eggs and being disturbed, which led to the abnormal development of embryos.

In order to solve this problem, you can try the following methods:

1. If the pigeon of the male pigeon is older, consider using Xiongbao for conditioning, or injecting half of testosterone propionate every day for 3 days to improve sperm motility.

2. Strengthen the nutritional supplement of breeding pigeons and provide sufficient health sand to enhance their physique.

3. Before pairing, conduct a systematic deworming and comprehensive cleaning for breeding pigeons to reduce the impact on hatching.

4. When hatching, try to reduce the interference of external environment, avoid cold eggs and excessive disturbance, and ensure the normal development of embryos.

If the above methods still fail to solve the problem, it is recommended to consult a veterinarian or a professional pigeon breeder for more detailed help and guidance.