Is an expiatory payment (kaffarah) obligatory for one whose owl, which he had cared for, died, knowing that it died after its health had improved and he had intended to release it, and this occurred during the days of Hajj?

You did well when you fed and watered the incapacitated bird, for in the two Sahih collections, the Messenger of Allah, peace and blessings be upon him, said: "For every living being with a moist liver, there is a reward." It is not permissible to confine an animal and not feed it, for the Messenger of Allah, peace and blessings be upon him, said: "A woman entered Hellfire because of a cat she tied up; she neither fed it nor let it eat from the vermin of the earth." It is obligatory to treat animals kindly and feed them, and this is especially emphasized during the sacred months. We hope that you will not incur sin for what happened, as long as you did not intentionally kill it, according to the Almighty's saying: "And there is no blame upon you for that in which you have erred, but [only for] what your hearts intended." There is no expiation, but if you give charity or perform any good deeds, there is hope for reward in that.