Duck at the veterinarian

A woman brings her duck to the vet because the duck is not very responsive. She is very worried.
Finally, the ducks in on the veterinary table, and the vet performs his inspection. After a couple of minutes, the vet turns to the woman and sadly shares with her: “I’m sorry but your duck passed away”.
The woman, very distressed, insists “I love my duck. How can you be so sure that he is no longer alive? You haven’t done any tests… he could be in a coma for all we know”.
The vet shakes his head and goes to a separate room where he comes back with a labrador. The lab sniffs the duck from top to bottom, then turns to the vet and shakes his head.
The vet then goes to get a cat. The cat sniffs the duck thoroughly as well, but with the same result: the cat turns to the vet and shakes his head.
The vet confirms to the lady: your duck did pass away: it’s now confirmed by our lab report and cat scan.