On the authenticity of the hadith
Basically the matter which creates confusion in this narratiion is primarily is the addition:
... and a tame sheep came in and ate it
This addition was compiled by ibn Majah, imam Ahmad and abu Ya'ala in their Musnad and by at-Tabarani in his al-Mo'jam al-Awsat via ibn Ishaaq the known "biographer" of the prophet, who is an ambivalent narrator. His narration is only accepted by hadith scholars if it goes along with that of other trustworthy narrators.
In this case his narration is in disagreement or has an addition to that of two of the most trustworthy narrators among the hadith scholars of Madina: Yahya ibn Sa'id al-Ansari which appears in Sahih Muslim with the wording:
There was revealed in the Holy Qur'an ten clear sucklings, and then five clear (sucklings).
and imam Malik (see here in al-Muwatta', in Sahih Muslim and Sunan an-Nasa-i) with the wording:
"Amongst what was sent down of the Qur'an was 'ten known sucklings make haram' - then it was abrogated by 'five known sucklings'.
When the Messenger of Allah, may Allah bless him and grant him peace, died, it was what is now recited of the Qur'an."
So this version includes an addition saying that some people didn't know that it was abrogated when the prophet () died.
Note that the wording of imam Ahmad's and ibn Majah's narrations have a slight difference.
Furthermore here a few statements and qualifications of the hadith narrations of Muhammad ibn Ishaaq:
- Hanbal ibn Ishaaq said: I heard Abu ‘Abdullah say: The narration of Ibn Ishaaq cannot be used as proof.
- ‘Abdullah ibn Ahmad said: He – i.e., Ahmad ibn Hanbal – did not use his reports as evidence when discussing what is Sunnah.
- Ayyoob ibn Ishaaq said: I asked Ahmad ibn Hanbal: O Abu ‘Abdullah, if Ibn Ishaaq is the only narrator of the hadith, will you accept it? He said: No, by Allah, for I have seen him putting together the words of many narrators in a single hadith, and not separating the narration of one person from that of another.
- The commentators on the Musnad of Imam Ahmad said (about the given hadith narration):
Its isnaad is da‘eef because the only one who narrated it was Muhammad ibn Ishaaq, and its text contains something odd. (See islamqa #175335)
So far we could clarify that this hadith has sound and well documented part, but it includes an addition that is odd and was not backed up by any trustworthy narration!
On breastfeeding that causes a prohibition for marriage and breastfeeding adults
Nevertheless ibn Majah narrated another hadith in his Sunan on the topic of breastfeeding adults which you may find here and also in Sunan an-Nasa-i and Sahih Muslim.
Also we couldn't make out the part that was referring to breastfeeding adults in the other narrations. This may mean that this addition has an issue or that the ruling of ten times was general in first place (if we try to find a consensus between the different narrations).
Note that many narrations show that there was no "breastfeeding" of adults, but the mother milk was milked and then consumed by an adult from a vessel.
Also be aware that there are 9 opinions on the duration of breastfeeding that may cause a prohibition of marriage (Source Injaz al-Hajah انجاز الحاجة شرح سنن ابن ماجة, Vol. 5 page 193 ff):
- The majority (this covers the views and statements of the four sunni madhhabs and most of the sahabah and tabi'yn) says only a breastfeeding during the two first (lunar) years of life count.
Imam abu Hanifa added a caution-time of six months.
- While the second view is that the time that counts is only before the weaning some of those whom have been reported to hold this view are Umm Salamah (), az-Zuhri, al-Awza'i, Qatadah and 'Ikrimah.
- The third view is that breastfeeding that counts is that of a child without giving a specific end time (but puberty would be such a time) which was reported as the view of ibn al-Musayyib, ibn 'Umar and the majority of the wives of the prophet ().
- The fourth view is 30 months which was reported as a view of abu Hanifa (see earlier) and Zufar.
- The fifth view is that of the two first years of life and what comes close to them which was reported as a view of imam Malik.
- The sixth view is that of 3 years which was reported as the view of many among the scholars from al-Kufa.
- The seventh view is seven years and was reported as a statement of 'Umar ibn 'Abdal-'Aziz.
- Rabi'a has been reported that it is two years and twelve days (8th view) and
- finally some say in case of need there's no limitation as one may for example want to allow a foreigner to enter and visit a non-mahram woman for some purposes.
Ahadith on breastfeeding adults are used to show that breastfeeding creates a prohibition for marriage for people who where foreign to each other. And this is the view of 'Aishah() , 'Urwa ibn az-Zubayr, al-Laith ibn Sa'ad, 'Ataa' ibn abi Rabah, ibn 'Uliyyah and ibn Hazm against the view of the majority saying that this tahreem (prohibiton) applies only for the two first years based on:
Mothers may breastfeed their children two complete years for whoever wishes to complete the nursing [period] … (2:233)
Sheikh Muhammad 'Ali al-Janbaaz in his commentary on Sunan ibn Majah (Injaz al-Hajah انجاز الحاجة شرح سنن ابن ماجة, Vol. 5 page 193 ff) quoted the above statements and views and commented the statement:
..." breastfeeding an adult ten times was revealed"
Saying that this doesn't necessarily mean that the same rule applied to children.
Another reference islamweb #12905 (in Arabic).