viruses Article Susceptibility of Chickens to Porcine Deltacoronavirus Infection Qingqing Liang 1,†, Honglei Zhang 1,2,†, Bingxiao Li 1, Qingwen Ding 1, Yabin Wang 1,2, Wenming Gao 3, Donghui Guo 3, Zhanyong Wei 1,2,* and Hui Hu 1,2,* 1 Department of Preventive Veterinary Medicine, College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, Henan, China;