What is wrong with my litter of Puppies!?

Hi, I had a litter of lab puppies born 01/11/13.

They have snotty noses and a cough that is more like a hacking and gagging cough.

Here is the story.

At 9 Days old: 1 of the puppies started having a congested breathing sound.

 AT 10 days old: Several of them were breathing like that.

At 11 Days old: 2 of the puppies started the cough, (Hacking gagging sound). I called the vet and we put them on Clavamox.

By 15 days: their cough would not stop! They would wake up coughing. Their cough was very constant.

At 17 Days: I took them to the vet. She said it sounded like Aspiration Pneumonia and gave them a shot of penicillin. She said they are happy healthy fat puppies. They did not act sick whatsoever. The cough slowed down in some and completely stopped in others.

By 19 Days, the cough came back in all of them.

Today is the 20th day, I've gotten another round of penicillin shots to give them tonight. They have been on Clavamox since the 23rd. They take it morning and night. I have not seen any improvement whatsoever. They are $600 Labrador Retriever Puppies. There are 12 Puppies, only 4 are not yet reserved. I have spent in vet bills for this litter nearly $600 in medications for them and momma, vet bills, food and everything! I'm doing my best and I'm thinking that maybe I need someone elses expertise.

I don't know what else to do. Please any and all ideas are appreciated!

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