Study of Physiological Changes as a Result of Oil Gland Removal And/or Burning the Rear Comb in Low Productive Hens

A total number of 240 Mandarah laying hens at 70 weeks of age (End of 52 weeks of egg production) were used to investigate the impact of removing the oil gland and / or burning the rear comb on egg production traits when the percentage of egg production decreased to 17.5%. The birds were divided into four equal groups. The first group served as a control group, the second group had surgically removed the oil gland, the third group was burned by fire at the rear comb and the birds of last group were treated in the same way as done in the second and third groups. Hens were housed in individual cages. Feed and water were given ad. Libitum and a photo period was 16 L: 8D. Egg production traits and some blood constituents were recorded through the six weeks after treatment. The main results could be summarized as follows: 1-Hens started laying eggs again after 6.53, 7.20 and 6.03 days of treatment for the second, third and fourth groups, respectively. 2Average egg production percentage during the six weeks after treatment was 12.06, 31.11, 29.05 and 34.84%, while the average egg weight was 49.27, 51.69, 48.79and 52.76 g. for the first, second, third and fourth groups, respectively. 3The fourth treatment improved both of shell weight percentage (14.20%), shell thickness (0.32 mm) and Haugh units (91.25). 4Treatment in the fourth group improved the relative weight of thyroid, ovary and oviduct as compared to the other treatments. J.Agric.&Env.Sci.Alex.Univ.,Egypt Vol.7 (2)2008 711 5Birds in the fourth group had higher values for Estrogen (E2), Progesterone (P4) hormones and had a lower ratio between E2/P4. 6Also, treatment in the fourth group had a higher values than the other treatments for blood serum constituents (Albumin, total lipids, glucose and Alkaline phosphatase) while the reverse was observed for testosterone, total proteins, calcium and phosphorus. In conclusion, these results indicate that the group treated by removal oil gland and burning by fire the rear comb had higher significant means for all most studied traits when the plateau of egg production had decreased.