Eggs or female reproductive cells are formed well before birth in a huge number (primordial oocytes). But, the number of oocyte decreases after birth constantly (there are 2 million oocytes at birth and 40,000 of them in puberty). At menopause, no egg cells are left.
On the other hand, the first sperms are formed only from puberty, but the production of those cells never stops.
The food eaten by the chicks goes up by 2.5 each time. I believe the independent variable is the number of days and the independent variable is the food given to the chicks.
