Mercy to animals earns Allah's forgiveness. The Prophet ﷺ told of a man who gave water to a thirsty dog, so “Allah thanked him and forgave him.” They asked: “Is there reward for us in animals?” He said: “In every living creature there is reward.” (al-Bukhārī). He also forbade harming animals in the face or branding them there.
العربية: عن أبي هريرة رضي الله عنه أنّ رسول الله ﷺ ذكر رجلًا سقى كلبًا من العطش، «فشكر الله له فغفر له»، قالوا: يا رسول الله وإنّ لنا في البهائم أجرًا؟ قال: «في كل كبدٍ رطبةٍ أجر». (البخاري).
Be gentle with animals — feed them, don't overload or harm them; mercy to any creature is rewarded.