Contrasting effects of pre- and posthatch exposure to gonadal steroids on the development of vocal, sexual, and aggressive behavior of young domestic fowl.

Prehatch treatment of domestic chicks with 17 beta-estradiol dipropionate (EDP) reduces later testosterone-facilitated sexual behavior, crowing, and suppression of peeping. Prehatch treatment with 5 alpha-dihydrotestosterone propionate (DHTP) reduces later testosterone-facilitated aggressive behavior and produces greatly enhanced avoidance that interferes with sexual behavior in some test situations. It also disturbs crowing by removing trilled call elements and increasing the number of elements/crow but has little effect on crowing posture. The majority of these results can be understood as "demasculinizing" effects of gonadal steroids on the developing male fetus, but the possibility that some result from more extreme pathological changes is also discussed. Posthatch treatment with DHTP facilitates attack and cackling but has no effect on sexual behavior or crowing; the synthetic androgen R1881 has similar effects on cackling and also has no effect on sexual behavior or crowing. Posthatch treatment with EDP enhances sexual behavior but has no effect on attack; the aromatase inhibitor 1,4,6-Androstatrien-3,17-dione (ATD) blocked the suppression of peeping by testosterone but had no effect on testosterone-facilitated sexual behavior. Combined posthatch treatment with EDP and DHTP facilitated crowing although treatment with either steroid alone was ineffective.