Ornithologists commonly measure birds' feathers as a proportion of total body weight. According to Cobb-Vantress, a 5-pound broiler chicken's feathers weigh about 74 grams or 2.6 ounces, or 3.3 percent of its body weight. Since that chicken has some 9,000 feathers, each one weighs about 0.0082 grams.
On wild birds, the number and weight of feathers vary widely - from 1,000 feathers on a hummingbird to more than 25,000 on a swan, according to the Prairie Research Institute of the Illinois Natural History Survey. The feathers represent a higher proportion of the wild bird's total weight than the proportion for a commercially-raised chicken. For wild birds, feathers can account for 15 to 20 percent of their total weight.