According to an article published in Time magazine on November 14th, 1969, Tisa Farrow suffered three mishaps while shooting the film on location, near Toronto. First, she stepped in a groundhog hole and pulled a leg tendon. Then, while hobbling with a cane, she was bitten by a rabid cat which required her to get 16 rabies shots in her stomach. Lastly, she was kicked in the stomach during a fight in a restaurant.
Offering an impressive soundtrack for a low-budget film, "Homer" is especially notable for being the first film to feature a song by Led Zeppelin. Portions of the song "How Many More Times," which was released on the album "Led Zeppelin I" in January 1969, are played three times during the course of the film.
Tisa indeed did get rabies shots. Others did too. What occurred was that during the filming there was an outbreak of disease within the farm animals on the property. The cows had to be killed and buried. Anyone who came into contact with any of the animals had to get shots. Tisa had been in contact with the farm's cat..
The owners of the farm where the movie was shot also had a son about Homer's age, who also played guitar. Just like in the film he too ran away from home after the film was completed.