SADDLE RIVER, N.J., Aug. 17  After spending the better part of two decades knocking on more doors than most people will in a lifetime, Fred Ferguson, a delivery driver with DHL Worldwide Express, has seen his share of sights strange and unpleasant.

But what Mr. Ferguson witnessed as he peered through the glass door of a colonial style home here in one of New Jersey’s most exclusive towns the other day left him groping for adjectives: a handful of cats and dogs, fur matted and unkempt, walking aimlessly amid piles of animal feces that in parts of the house was nearly knee high.

“What’s a worse word than ‘disgusting’?” Mr. Ferguson, 40, asked. “I didn’t know if somebody was dead in the house.”

Not somebody, but something: Twenty-three pets were decomposing inside, some so badly that the authorities could not tell whether they were cat or dog. And the live animals Mr. Ferguson saw were among more than 100 dogs and cats that the authorities said had been neglected for years by an upper-middle-class couple here in a home valued at $2.4 million.