The CDC and its Advisory Committee on Immunization Practices (ACIP) now recommend that all adolescents aged 11-18 get vaccinated against meningococcal disease. That's not a radical change from the CDC's old meningitis vaccination schedule. In the past, vaccination of adolescents and young adults was recommended to coincide with specific ages or events, the CDC's Tom Clark, MD, said at a news conference today.
Cool Facts. 1  American Crows congregate in large numbers in winter to sleep in communal roosts. 2  Young American Crows do not breed until they are at least two years old, and most do not breed until they are four or more. 3  In some areas, the American Crow has a double life.
EGG PRODUCTION CYCLE. Birds usually start to lay at around five months (20-21 weeks) of age and continue to lay for 12 months (52 weeks) on average, laying fewer eggs as they near the moulting period. The typical production cycle lasts about 17 months (72 weeks) and involves three distinct phases, as follows.n the fourth column the actual number of eggs produced is shown. On average a bird produces 208 eggs over a twelve-month period, which is a weekly production rate of four eggs per bird. At 21 weeks of age 20 eggs are produced (five birds produce four eggs each) and at 22 weeks 40 eggs are produced, etc.