What is the ruling on a sheepdog remaining after the sheep have been sold, when it does not enter the house but sleeps outside or stays in its yard?

The Sunnah indicates the prohibition of keeping a dog except in specific, exempted cases. Whoever keeps a dog will have two Qirats deducted from his reward each day. The majority of jurists permit keeping a dog for hunting, livestock, and agriculture. In response to your question: if you intend to buy sheep, you may keep the dog to guard them; otherwise, you may not. Do not allow it into the house's courtyard. If it's possible to transport it in a car and leave it far from the house, then do so. If the dog returns despite being driven away, prevent it from entering the house or its courtyard. Do not give the dog food specifically as if it were your property, but rather as you would feed any other animal in the street; this will be a charity for you.