1.

(number of chickens) -------------------------- multiplied or divided by 2 (male and female) (number of families)

2. Apparent digestibility of nutrients, for example protein.

Crop protein content (dead bird) ¿ Feacal protein content (live bird) ----------------------------------------------------------------------------------- x 100 Crop protein content (dead bird)

3.True digestibility of nutrients, for example protein.

Crop protein content (dead bird) ¿ Ileum digesta protein content (live bird) ------------------------------------------------------------------------------------------- x 100 Crop protein content (dead bird)