Bukhari

Hadith Commentary:
From this hadith, Imam Bukhari rahimahullah deduced that the exchange of one animal for another animal is permissible.
Similarly, the exchange of a slave for a slave, or a slave-girl for a slave-girl, is also permissible, because all of these are, after all, living beings (animals).
And this will be the ruling for every living being (animal).
Some have raised the objection that in this hadith, there is no mention of increase or decrease (in quantity), nor of credit (deferred payment).
The answer to this is that Imam Bukhari rahimahullah has alluded to another chain of this hadith, which Imam Muslim has recorded.
In that narration, it is mentioned that the Prophet sallallahu alayhi wa sallam purchased Safiyyah radi Allahu anha by giving seven slave-girls.
Ibn Battal said: When the Prophet sallallahu alayhi wa sallam said to Dihyah radi Allahu anhu, “Take any other slave-girl from among the captives in exchange for Safiyyah radi Allahu anha,” then this was a sale of a slave-girl for a slave-girl on credit, and this is its very meaning.
(Wahidi)
Dihyah al-Kalbi radi Allahu anhu was the son of Khalifah al-Kalbi.
He was a companion of high rank.
He participated in the Battle of Uhud and all subsequent battles.
In 6 AH, the Prophet sallallahu alayhi wa sallam sent him to the court of Caesar, the king of Rome, with a blessed letter.
Caesar wished to become Muslim, but out of fear of his Christian subjects, he did not accept Islam.
This Dihyah radi Allahu anhu is the same companion in whose form Jibril alayhis salam would often come to the Prophet sallallahu alayhi wa sallam.
In the end, Dihyah al-Kalbi radi Allahu anhu went to the land of Sham (Greater Syria) and remained there until the era of Muawiyah.
Many of the Tabi‘in narrated from him.
In the hadith of Safiyyah radi Allahu anha, it is his mention that appears.

Hadith Commentary:
(1)
The mentioned narration is extremely brief.
In other narrations, there is detail that the Messenger of Allah (sallallahu alayhi wa sallam) bought Safiyyah (radi Allahu anha) from Dihyah al-Kalbi (radi Allahu anhu) in exchange for seven slaves.
(Musnad Ahmad: 3/123)
Similarly, Jabir (radi Allahu anhu) narrates that the Messenger of Allah (sallallahu alayhi wa sallam) bought one slave in exchange for two slaves.
(Sahih Muslim, al-Musaqat, Hadith: 4113(1602))
(2)
It is narrated from Abdullah ibn Amr (radi Allahu anhu) that the Messenger of Allah (sallallahu alayhi wa sallam) ordered him to prepare an army. When the camels ran out, he instructed him to take camels on credit, to be repaid when the camels from charity arrived.
Abdullah ibn Amr says that he would take one camel in exchange for two camels from charity, meaning the payment of two camels would be made when the charity camels arrived.
(Sunan Abi Dawud, al-Buyu', Hadith: 3357)
There is a narration that appears to contradict these narrations, in which the Messenger of Allah (sallallahu alayhi wa sallam) forbade the sale of an animal for an animal on credit.
(Al-Sunan al-Kubra lil-Bayhaqi: 5/288)
The scholars of hadith have responded that in this narration, what is meant by "on credit" is that both sides are on credit, and such a transaction is not permissible according to anyone.
(Ma'alim al-Sunan: 5/29)
According to our inclination, the sale and purchase of an animal for an animal, whether on credit or with an increase or decrease, is absolutely permissible.
And Allah knows best.