3Chmielewski R, Swayne DE. Avian influenza: public health and food safety concerns [ J ]. Annu. Rev. Food Sci. Technol. , 2011,2:37 -57.
4Mustafa MY, Muneer MA, Anjum AA, et al. Influence of stocking density on immune response of broilers against newcastle disease virus [J]. Pak. J. Life Soc. Sci., 2010,8(1) :7 - 10.
5Turkyilmaz MK. The effect of stocking density on stress reaction in broiler chickens during summer [ J ]. Turk. J. Vet. Anim. Sci, 2008,32(I):31-36.
6Hoye B J, Munster V J, Nishiura H, et al. Reconstructing an annual cycle of interaction: natural infection and antibody dynamics to avian influenza along a migratory flyway[ J]. Oikos, 2011,120:748 - 755.