The Prophet (ﷺ) as saying: If anyone buys sheep whose udders have been tied up, he has option for three days: he may return it if he desires with a sa' of any grain, not (necessarily) wheat.
Sunan Abi Dawud Book 24, Hadith 29
← Previous Hadith The Messenger of Allah (ﷺ) as saying: Do not go out to meet riders to conduct business with them ; none of you must buy in opposition to one another; and do not tie up the udders of camels and sheep, for he who buys them after that has been done has two courses open to him after milking them: he may keep them if he is pleased with them, or he may return them along with a sa' of dates is he is displeased with them.

Sunan Abi Dawud Book 24, Hadith 28 Next Hadith → The Messenger of Allah (ﷺ) as saying: If anyone buys sheep or goat whose udders have been tied up and he milked it, he may keep it if he is pleased with it, or he may return it if he is displeased with it. There is one sa' of dates (which he must give to the seller) for milking it.

Sunan Abi Dawud Book 24, Hadith 30