Abstract
Muscovy ducks reared commercially are often bill trimmed to prevent feather pecking and cannibalism. Bill trimming has been criticized because of its potential to cause acute and chronic pain, but little is known about the beneficial effects of bill trimming on welfare of ducks. The aim of this study is to realize the effects of three different methods of bill trimming (cutting by scissor, hot blade and hot searing) on bill related behavior, body weight and welfare of Muscovy ducks. A total of 48 (sixteen days of age) Muscovy ducks were allotted equally to four equal groups. The first was a control (C) group without bill trimming, the second; scissor (S) bill trimmed by scissor, the third; hot blade (HB) bill trimmed by hot blade and hot searing (HS) bill trimmed by touch cautery blade for few second. Bill related behavior of ducks was recorded by video camera for six weeks post-trim using scan sampling. Ducks were weighed weekly. At the end of experiment (9 week old) blood samples were collected for Heterophil /lymphocyte ratio and level of corticosterone hormone. The different methods of bill trimming had non-significant effects on ingestive behavior, while trimming by scissor and hot blade significantly reduce aggressive pecking than control group. Body weight of hot blade trimming group was significantly lower than the other three groups. Bill trimming by scissor, hot blade, or hot searing didn’t influence neither blood corticosterone level nor heterophil lymphocyte ratio.

Key words: Muscovy ducks, Bill trimming, Behavior, Welfare.