Sudden pink eye & droopy, pink, lower lid

Question
I breed Labrador Retriever's.  This evening I noticed that three of the puppies, (now 8 weeks old), have a bit of a droopy lower lid and the eyes are pink, especially the lower portion.  This happened to two of mine in the last litter around the same age.  The last time I gave them Amoxicillin and it cleared.  It's the middle of the night and the vet is closed, but I had to try to research.  Before I try just giving Amox with this litter, I'd like to know what it might be.  Can they easily get "pink eye" and what could possibly be happening to have this happen two litters in a row?  Do they just play so much that in their roughhousing they manage to get their dirty paws (as puppies always seem to immediately walk in their brother/sister's poop before you can bend down to get it!) infect their eyes?  I consider myself a very careful and picky breeder.  Am I doing something wrong?  Two of my puppies are scheduled to go to their new homes the day after tomorrow and I don't want them to go with anything wrong.

Answer
The fact that you experienced this before and it cleared with Amoxicillin makes me think that yes, it could be bacterial conjunctivitis and that you need to start them again on some antibiotics.
I hope you are dosing them for 10 full days otherwise you will breed resistant bugs around your house.

They could just have an 'infection' from the dirt and feces in their eyes, but conjunctivitis is just that anyway. There are more than one kind of IC-one is viral. That usually is self-limiting and goes away in about a week but is highly contagious also.

I know it's hard to keep them clean but try some pea gravel for them to play on and that might cut down on the infections. You can spray the gravel with a diluted bleach mixture also and that helps. 1 part bleach to 10 parts water.
If in doubt, always check with your vet before giving any drug to puppies.