Table 1.

Survival and feeding rates of D. gallinae with photoperiod of 1:23 h L:D

Variable	Photoperiod	Days post-challenge
		7	14	21	28
Feeding rate (%)	1:23 h L:D	52.0 ± 7.0	36.7 ± 1.1	44.8 ± 5.9	50.5 ± 1.9
Survival rate (%)	1:23 h L:D	98.9 ± 0.6	98.9 ± 0.2	98.1 ± 0.1	98.6 ± 0.1

Notes: Chicks were challenged with 220 D. gallinae at 0 dpc and kept on prolonged darkness photoperiod of 1:23 h L:D. The numbers of dead and fed D. gallinae were recorded at 7, 14, 21 and 28 dpc. Survival and feeding rates were calculated as follows: Survival rate (%) = Number of surviving mites/Total number × 100%; Feeding rate (%) = Number of feeding mites/Total number × 100%. All values are shown as mean ± SD from three independent experiments