2,602. When Buyers Need Not Be Informed

Hilchos Shechita 12:15

The previous halacha, about informing a buyer, applies when we see that the new buyer is eager to purchase at the end of the day, so we assume that he intends to slaughter it right away. If there’s still plenty of time left in the day, he need not inform the buyer, because he might not intend to slaughter until the next day.

Hilchos Shechita 12:16

If one sells the mother animal to a groom and the daughter animal to his bride, he must inform them, because they will surely slaughter them on the same day. The same is true in all comparable cases.