Vet bill

A lady takes a cage bird to the vets. It's lying on the bottom of the cage not moving.
The vet takes one look and pronounces it dead.
"Oh no!" wails the woman. "Not my little Joey! He can't be dead!"
The vet assures her that the bird is deceased but she demands a second opinion.
"OK." says the vet and leaves the room.
After a few seconds the door opens and in walks a labrador dog. It crosses to the cage, sniffs the bird, shakes it's head and walks out. Moments later in walks a cat and does the same thing.
The vet reappears. "Right madam, that will be $300."
"What!" exclaims the woman. "The last time I brought little Joey here it only cost $50!"
"Yes madam, but this time you have to pay for the lab report and cat scan."