Praise be to Allah.
“Honouring the deceased means burying him” is not a hadeeth; rather these are the words of one of the fuqaha’.
See Mukhtasar Khaleel by al-Kharashi, 2/91
As-Sakhkhaawi (may Allah have mercy on him) said in al-Maqaasid al-Hasanah (p. 141):
I did not find the hadeeth “Honouring the deceased means burying him” in any marfoo‘ report (i.e., attributed to the Prophet (blessings and peace of Allah be upon him)). Rather it was narrated by Ibn Abi’d-Dunya in his Kitaab al-Mawt, via Ayyoob as-Sakhtiyaani. He said: It was said that a sign of honoring the deceased on the part of his family is their hastening to bury him. End quote.
But the meaning is correct and is in accordance with the Sunnah.
We do not say concerning an animal, when it dies, that part of honoring it is burying it, as we say about human beings. But if burying it will ward off harm from the Muslims, then it is prescribed to do so, because burying it in that case comes under the heading of removing something harmful from the road used by the Muslims.
If the Muslims will be harmed by it and bothered by its smell, then it is obligatory to bury it or take it far away from the highways and byways used by the people. Hence it is prescribed to bury it, in order to ward off harm from the Muslims, not just because it has died.
Al-Bukhaari (1492) and Muslim (363) narrated that Ibn ‘Abbaas said: A sheep was given in charity to a freed slave woman of Maymoonah, but it died. The Messenger of Allah (blessings and peace of Allah be upon him) passed by it and said: “Why don’t you take its hide and tan it, and make use of it?” They said: It is dead, O Messenger of Allah (i.e., it died of natural causes and was not slaughtered properly). He said: “It is only haraam to eat it.”
So he encouraged them to make use of its hide, and he did not tell them to bury it.
The scholars of the Standing Committee were asked about vermin and animals and so on; should they be buried, or left unburied on the ground?
The matter is broad in scope, because there is no text in sharee‘ah to indicate that it is prescribed to bury them or to forbid doing so. But it is preferable to bury them so that they will not harm or bother anyone.
End quote from Fataawa al-Lajnah ad-Daa’imah, 8/444-445
See also the answer to question no. 105365.
And Allah knows best.