Beak trimming: blade temperature and welfare. (#664)
To diminish severe feather pecking and cannibalism beak trimming is performed. Beak quality delivered by an individual trimmer may vary. One possible cause may be variation in blade temperature. In this experiment blade temperature is compared with beak form, some zoo technical data, plumage condition and cannibalism.
Hens were kept on the floor (45 individuals per compartment). In four compartments the hens remained untrimmed. Twenty four compartments were trimmed at 6 weeks, 1/3 of the compartments at 650º C (the advised “cherry red” colour), 1/3 at 450º C and 1/3 at 850º C.
We assumed that the more deviant the trimmed beak is the lower the welfare. At 16 weeks the beaks of four hens out of each compartment were scored (0: as untrimmed; 4: extremely bad). Most traits were significantly higher the higher the temperature: weakness above (1.1, 1.4, 1.6, sign), below (1.4, 1.8, 1.9, sign) and “swollen” above (0.4, 0.6, 0.7, sign), below (0.8, 1.1, 1.2, sign). Spots (healing wounds) was above: 0.2, 0.1, 0.2, ns, below: 0.8, 0.8, 1.2, sign. Also the lower the temperature the more normal the general impression of the beaks (sign.). These results suggested that the lower the temperature the better the welfare of the trimmed hens.
A lower food intake and growth in the first week after trimming could also be an indication of a lower welfare. These differences were ns. Also differences in weight, food intake and uniformity at week 16 were ns.
A worse condition of the plumage and cannibalism could be an indication of a lower welfare in flock mates. However, at 16 weeks these differences were ns (cannibalism did not occur). In untrimmed hens both measures were worse.
A more elegant solution to diminish severe feather pecking and cannibalism could be selection against these traits. See http://journal.frontiersin.org/Journal/10.3389/fgene.2014.00266/full