Effect of incubation temperature on the gross pathology of turkey embryos.

1. Turkey eggs were incubated at 36.5, 37.5 and 38.5 degrees C. The age of mortality, the incidence of malpositions and the incidence of morphological abnormalities were recorded from all unhatched eggs. 2. Eggs incubated at 36.5 degrees C hatched later than eggs incubated at 37.5 degrees C but did not differ in age of mortality or incidence of malpositions and abnormalities. 3. Eggs incubated at 38.5 degrees C hatched significantly less well than eggs incubated at 37.5 degrees C and showed significant differences in time of embryo mortality. Overheated embryos had a mortality peak between 15 and 20 d of incubation and an increased mortality after 24 d of incubation. 4. Overheated eggs were characterised by a high incidence of embryos with head in small end, with excess albumen, ruptured yolk sacs, oedematous heads, eye cataracts and swollen down-plumules.