Complex sentence: Some of the early breeders of Miniature Schnauzers ignorantly thought the White puppies were albino because when they are first born they have pink skin and noses and destroyed them at birth mistakenly thinking they were albino.
Split into simpler sentences: Some of the early breeders of Miniature Schnauzers ignorantly thought the White puppies were albino because when they are first born they have pink skin and noses. Many early breeders destroyed them at birth mistakenly thinking they were albino.