A geometric model and an unbiased estimation using vertical section for villous surface estimation were compared. Small bowels of 10 domestic fowls were dissected and 8cm of bowl segments from mercel’s diverticulum towards distal direction were subjected to estimation. In geometric model transversal sections of bowel and a test lattice consist of vertical and horizontal test lines were used. For unbiased estimation; bowel was opened along its length, laid flat on a substratum and sectioned vertical to the substratum. Then a cycloid test lattice was used. It was found that the estimated total surface due to villi was significantly different between the two methods.