Bukhari

Hadith Commentary:
It is said that at first, the rooster crows at midnight.
In Ahmad and Abu Dawud, it is stated: Do not speak ill of the rooster, for it awakens (people) for prayer.
It is the habit of the rooster that as soon as dawn (fajr) breaks and when the sun declines (from its zenith), it crows.
This is the natural disposition (fitrah) created by Allah. First, Imam Bukhari rahimahullah described the nightly vigilance of Dawud alayhis salam.
Then, he established that the practice of our Prophet sallallahu alayhi wa sallam was in accordance with this. From these two hadiths, it is derived that he would sleep during the first part of the night until midnight, then rise at the time of the rooster’s crowing, that is, at midnight.
Then, from the following hadith, it is established that he would sleep at the time of sahar (pre-dawn).
Thus, the practice of the Prophet sallallahu alayhi wa sallam and Dawud alayhis salam became identical.
‘Iraqi has written in his book of biography (sirat) that the Prophet sallallahu alayhi wa sallam had a white rooster.
And Allah knows best what is correct.

Hadith Commentary:
The rooster gives its first call after midnight.
At that time, you would stand for the Tahajjud (night prayer).

Hadith Commentary:

Benefits and Issues:
The Prophet (sallallahu alayhi wa sallam) would sometimes rise at midnight, sometimes a little before or a little after midnight, and sometimes he would rise at the crowing of the rooster, and the rooster crows after midnight.

1617. Commentary:

➊ The rooster generally crows after midnight. In some other narrations, it is mentioned that the Prophet sallallahu alayhi wa sallam would sleep until half the night had passed, then remain awake (performing prayer) for a third of the night, and then sleep for the final sixth part. See: (Sahih al-Bukhari, Kitab al-Tahajjud, Hadith: 1131, and Sahih Muslim, Kitab al-Siyam, Hadith: 1159). This division is from after the ‘Isha prayer until the call to Fajr, because this is considered the night for Muslims. The rest of the time is for being awake, that is, for the times of prayer.

➋ Since righteous people wake up for prayer upon hearing the rooster’s crow, people refer to its sound as an adhan (call to prayer). The Messenger of Allah sallallahu alayhi wa sallam also said: The rooster crows upon seeing the angels, so when you hear the rooster’s crow, say: (Allahumma inni as’aluka min fadlik) (Sahih al-Bukhari, Kitab Bad’ al-Khalq, Hadith: 3303 and Sahih Muslim, Kitab al-Dhikr wa’l-Du‘a, Hadith: 2729). O rooster, how fortunate you are! One should adopt moderation in voluntary worship and not be excessive. Otherwise, a person becomes weary and cannot continue the practice.