Mutts to You (1938)

The stooges, professional dog washers, find a baby on a doorstep and, thinking it to be abandoned, take it home. When they read in the paper the baby is believed to have been kidnapped, they disguise Curly as a the baby's mother and try to sneak past the local cop. They are caught, but when the baby's parents show up and realize what happened, the result is a happy ending.