Animal husbandry with surrounded ventilation window, which are negative ventilation, automatically opened with negative pressure. Materials: frame, blade and the bottom of the foam board is made by ABS plastic,. Advent- tags: indoor temperature can maintain a long time, it can significantly change the indoor air circulation, high temperature, cold; high strength, easy installation, ventilation effect is obvious, long service life, top type installation. The thickness of foam plate is20mm by 4 surface air draft.