I brought a brother of mine to the Prophet (ﷺ) to do Tahnik for him while the Prophet (ﷺ) was in a sheep fold of his, and I saw him branding a sheep. (The sub-narrator said: I think Anas said, branding it on the ear.)
Sahih al-Bukhari Book 72, Hadith 67
← Previous Hadith that Ibn `Umar disliked the branding of animals on the face. Ibn `Umar said, "The Prophet (ﷺ) forbade beating (animals) on the face."

Sahih al-Bukhari Book 72, Hadith 66 Next Hadith → I said to the Prophet, "We will be facing the enemy tomorrow and we have no knives (for slaughtering)' He said, "If you slaughter the animal with anything that causes its blood to flow out, and if Allah's Name is mentioned on slaughtering it, eat of it, unless the killing instrument is a tooth or nail. I will tell you why: As for the tooth, it is a bone; and as for the nail, it is the knife of Ethiopians." The quick ones among the people got the war booty while the Prophet (ﷺ) was behind the people. So they placed the cooking pots on the fire, but the Prophet (ﷺ) ordered the cooking pots to be turned upside down. Then he distributed (the war booty) among them, considering one camel as equal to ten sheep. Then a camel belonging to the first party of people ran away and they had no horses with them, so a man shot it with an arrow whereby Allah stopped it. The Prophet (ﷺ) said, "Of these animals there are some which are as wild as wild beasts. So, if anyone of them runs away like this, do like this (shoot it with an arrow).

Sahih al-Bukhari Book 72, Hadith 68