Final answer:
Bovine lice eggs usually hatch after 2 to 3 weeks of incubation. Bovine lice are most active during the winter months when cattle are kept indoors and experience stress.
Step-by-step explanation:
The incubation period for bovine lice eggs is typically around 2 to 3 weeks. During this time, the eggs develop and hatch into nymphs. The nymphs then go through several molts before reaching adulthood.
In terms of when bovine lice are the worst, they tend to be most active during the winter months when cattle are kept indoors and have close contact with each other. Cold weather provides a favorable environment for lice to infest and multiply. Additionally, lice populations can peak during times of stress for the cattle, such as during transportation or when their immune systems are weakened.