This is an old Soviet cartoon based on the folktale recorded by the Brothers Grimm. Despite the title, the musicians never arrive in Bremen.
"In the story a donkey, a dog, a cat, and a rooster, all past their prime years in life and usefulness on their respective farms, were soon to be discarded or mistreated by their masters. One by one they leave their homes and set out together. They decide to go to Bremen, known for its freedom, to live without owners and become musicians there.
On the way to Bremen, they see a lighted cottage; they look inside and see four robbers enjoying their ill-gotten gains. Standing on each other's backs, they decide to perform for the men in hope of gaining food. Their 'music' has an unanticipated effect; the men run for their lives, not knowing what the strange sound is. The animals take possession of the house, eat a good meal, and settle in for the evening.
Later that night, the robbers return and send one of their members in to investigate. He sees the Cat's eyes shining in the darkness and thinks he is seeing the coals of the fire. He reaches over to light his candle. Things happen in quick succession; the Cat scratches his face with her claws, the Dog bites him on the leg, the Donkey kicks him and the Rooster crows and chases him out the door, screaming. He tells his companions that he was beset by a horrible witch who scratched him with her long fingers (the Cat), an ogre with a knife (the Dog), a giant who had hit him with his club (the Donkey), and worst of all, the judge who screamed in his voice from the rooftop (the Rooster). The robbers abandon the cottage to the strange creatures who have taken it, where the animals live happily for the rest of their days."
Got that summary of the plot from Wikipedia.
I like the cartoon better than the story. Cute music and even cuter artwork.