What is a Chimney Sheep? A Chimney Sheep is a removable chimney draught excluder made from highly durable, naturally breathable Herdwick wool. The wool is felted to create a perfect plug for the chimney and a handle added for easy insertion and removal. A Chimney Sheep makes your home feel more comfortable by stopping warm air escaping and preventing cold air coming in as well as reducing wind noise, energy bills, CO2 emissions and any debris that may fall down your chimney. Read more Chimney Sheep Features A perfect fit When inserted into an open chimney flue, the woollen pad of a Chimney Sheep compresses to fit perfectly in flues of all shapes and sizes. Natural ventilation Other chimney draught excluders require a small gap to be left in your flue to allow ventilation.