Figure 3

Development phases of the chicks: (A) nestling, 0–25 days, birds on picture are 17 and 18 days, respectively. Mass gain at this phase is slow, (B) chick, 26–77 days, birds on picture are 44 and 45 days, respectively, (C) chicks, birds on picture are 61 and 62 days, respectively. Geometric growth until maximum weight is attained, (D) juvenile, 78–107 days, birds on pictures are 104 and 105 days, respectively. Weight is maintained up to 90–95 days when weight loss begins with the first attempts of flying.