Throughout the southern china,generally from lunar october to lunar march next year,while the northern provinces from lunar sepermber to next lunar april,feathers&down producted during this period called"winter-spring down"winter-spring down has full-grown and study down clusters,shining color,high fill power,fantastic quality,high unit production,mainly distributed in anhui ,jiangsu,hunan,zhejiang,shandong,jiangxi,sichuan and northeast three provinces,where in these regions are plenty of rivers and richer grasses,producing white shining feathers,full-grown down clusters with high fill power.