Narrated 'Abdullah bin 'Umar: Allah's Apostle said, "A woman was tortured and was put in Hell because of a cat which she had kept locked till it died of hunger." Allah's Apostle further said, (Allah knows better) Allah said (to the woman), 'You neither fed it nor watered when you locked it up, nor did you set it free to eat the insects of the earth."
Narrated Ibn 'Umar: The Prophet said, "A woman entered the (Hell) Fire because of a cat which she had tied, neither giving it food nor setting it free to eat from the vermin of the earth."
Narrated Abu Huraira: Allah's Apostle said, "While a man was walking he felt thirsty and went down a well and drank water from it. On coming out of it, he saw a dog panting and eating mud because of excessive thirst. The man said, 'This (dog) is suffering from the same problem as that of mine. So he (went down the well), filled his shoe with water, caught hold of it with his teeth and climbed up and watered the dog. Allah thanked him for his (good) deed and forgave him." The people asked, "O Allah's Apostle! Is there a reward for us in serving (the) animals?" He replied, "Yes, there is a reward for serving any animate."
Bukhari
Kindness to animals is definitely a rewarding thing