The phenomenon of rainbow-colored dog feces in the 1970s is often attributed to the widespread use of artificial dyes in dog food during that time. Many commercial dog foods contained a variety of synthetic colorants to make the kibble more visually appealing to pet owners, even though dogs themselves are not particularly concerned with the color of their food.
Over time, awareness about the potential health risks associated with artificial dyes and additives increased. As a result, there was a shift towards more natural ingredients in pet foods. Pet food manufacturers began to reduce or eliminate synthetic dyes from their products, opting instead for natural coloring agents or no added colors at all.
This change in formulation led to a decrease in the occurrence of brightly colored dog feces on sidewalks and other public areas. Today, most high-quality dog foods focus on nutritional value rather than aesthetic appeal, contributing to healthier pets and less colorful waste.