Effect of Cage Placement on Health Status of Laying Hens

Evaluation of cage placement on bird’s health was done to access the efficiency of the conventional battery cages as a housing system for laying hens in the highly demanding industry in tropical countries. Experimental birds were placed in House A in the lateral sixth northern battery cage (AN6L) beside cooling pads and medial northern battery cage (ANM) horizontally at the middle lower row in both sides-left and right. Each battery raw was divided into: first third beside pad (1W) consists of 130 cages; second third in middle (2W) which also consists of 130 cages and last third beside fans (3W) consists of 128 cages. The total birds in the two batteries were about four thousand and five hundred birds. In house B, experimental birds were placed in the lateral first northern battery cage (BN1L) beside northern pad, medial northern battery cage (BNM) in middle and lateral sixth northern battery cage (BN6L) beside southern pad vertically and horizontally from bottom in both sides (left and right). Each battery raw was divided into: First third beside pad (1W) consists of 520 cages; second third in middle (2W) consists also of 520 cages and last third beside fans (3W) beside fans consists of 512 cages, the total birds in the three batteries were about thirty thousand birds. Mortality and pathological changes were used in this study to evaluate the health status and welfare of Lohmann LSL Lite laying hens at different ages. Mortality of 4500 Lohmann LSL Lite laying hens at age 80 wks was recorded for twenty days in one lateral and one medial battery in House A; and it was recorded for 30000 Lohmann LSL Lite laying hens at age 57 wks for forty three days in two lateral and one medial battery in House B. The mortality in the two laying flocks at age 80 wks and 57 wks, in the first 20 days, was found to be 7.4% and 1.6% respectively. In the next 23 days in House B, it was found to be 1.7%. The mortality of the two flocks was significantly different. In the three positions- 1W, 2W, 3W- the mortality at a lateral (AN6L) and a medial (ANM) batteries in showed significant difference in the lateral ones of House A. The mortality in the three positions 1W, 2W, 3W of two laterals (BN1L and BN6L) and one medial (BNM) battery showed significant difference between the different positions of both lateral and medial batteries. Comparing house A and house B lateral and medial batteries for the mortality in the same position, 1W, 2W or 3W, revealed significant difference in 1W and 2W, whereas position 3W was found to be insignificantly different, and no significant difference between the lateral or medial batteries as a whole was detected when comparing them in the two houses. Post mortem examination of nine birds at age 80wks and fourteen birds at age 57wks revealed that the only possible effect of cage placement on the internal infection may be exerted by the direction of air current caused by the working exhaust fans.