Interaction of color and photointensity on preening behavior and ingestion of spray-applied biologics

Previous research has demonstrated that increased photointensity near the time of spray application can increase preening activity and ingestion of spray-applied material and can enhance establishment of, a competitive exclusion culture. In the present study, inclusion of selected colors had a marked effect on preening activity, with fluorescein or forest green combined with fluorescein causing the greatest increase in preening under conditions of constant lighting (92 FC before, during and after spray). Minimal effects of constant incandescent (80 FC) vs. fluorescent light (80 FC) source were observed, regardless of the color used. While addition of color improved preening activity under constant lighting, no additional increase in preening activity was observed when coloring was added to the spray applied under conditions of increasing photointensity. These data indicate that coloring of spray solutions for application to neonatal chicks can improve preening activity under conditions of constant lighting. However, optimization of photointensity near the time of spray application negates the need for addition of coloring and, in fact, increases-preening activity to levels not observed due to color addition to the spray solution under conditions of constant lighting.