YOU SAID:
They used to feed their dog.
INTO JAPANESE
彼らは彼らの犬を養うために使用されます。
BACK INTO ENGLISH
They feed their dogs will be used.
INTO JAPANESE
彼らは彼らの犬を養うが使用されます。
BACK INTO ENGLISH
They feed their dogs will be used.
That didn't even make that much sense in English.