"A large portion of the data used to derive the coefficients in Table 9-6 were determined with cecectomized birds; however, data from studies with conventional birds were also included. Cecectomy removes the majority of the hindgut area in poultry and eliminates most of the potentially confounding effects of the hindgut microflora on amino acid excretion. The surgical procedure is simple, and several laboratories are currently using the technique. Digestibility coefficients determined with cecectomized birds are often lower than those determined with conventional birds."The vast majority of studies aren't conducted on birds which have had cecectomies performed