other 2 treatments. However, at ages 21 (P = 0.012)
and 28 (P = 0.023) ducks under blue light were observed
drinking more often than ducks raised under
white or red lights (Figure 3B). At various ages, ducks
raised under red lights were observed to show fewer (P
= 0.032) preening and foraging behaviors compared to
ducks raised under white or blue lights (Figure 4A and
B, respectively). At all ages after d 7, ducks raised under
red light showed much less (P < 0.0105) activity
compared to ducks under white or blue lights. However,
at days 14 and 21, ducks under blue light showed extremely
high levels of activity (P < 0.0087) compared to
the other 2 light treatment groups. Figure 5 illustrates
our observations of duck activity.
Hormone data By d 7, ducks raised under blue light
showed considerably higher (P = 0.0009) plasma corticosterone
levels compared to ducks raised under white
or red lights. Conversely, ducks raised under blue lights
also showed lower (P < 0.021) levels of plasma GH compared
to ducks under white or red lights. Figure 6 illustrates
the levels of circulating cort and GH.