Is it permissible to sell a pregnant sheep or goat, and to increase its price due to its pregnancy?

There is no harm in selling a pregnant ewe, and her fetus is included in the sale by consensus if it is sold without specific conditions. As for increasing its price compared to a non-pregnant ewe, this depends on the mutual consent of the buyer and seller. The sale is valid if it occurs with their mutual consent, based on the Almighty's saying: "O you who have believed, do not consume one another’s wealth unjustly but only [in lawful] trade by mutual consent."