The Messenger of Allah ﷺ disliked horses with shikal markings.In another narration it is added, "Shikal means that the horse has a white marking on its right hind leg and its left foreleg, or on its right foreleg and left hind leg."
كان رسول الله ﷺ يكره الشكال من الخيل. وزاد في رواية: و الشكال أن يكون الفرس في جله اليمنى بياض وفي يده اليسرى، أو في يده اليمنى ورجله اليسرى.
Muslim narrated it in the Book of Leadership (1875:101) through several routes from Sufyan (that is, Thawri), from Salm bin Abdul-Rahman, from Abu Zura, from Abu Hurairah, and he related it. The addition occurs in the narration of Abdul-Razzaq from Sufyan with the same chain. It appears that this explanation comes from the companion or from someone below him in rank, and there are other opinions regarding the explanation of the "shikal" horse, which Nawawi mentioned in his commentary on Sahih Muslim (18/13). He said, "The scholars said, he disliked it only because it resembles a hobbled animal. And it has also been said that it is possible he had tried that type and found no excellence in it."