Collection of Behavioral Data
The ducks were video-recorded continuously for 5 d
each week, centered on d 7, 14, 21, 28, and 32. The video
footage was analyzed in 5-min segments, from 0600 to
1200 hrs. The activity level of each pen was determined
on a qualitative scale of 1 to 5 (1 = inactive; 5 = very
active). Preening, drinking, eating, and foraging behaviors
were also observed and quantified.