Help! My hens have stopped laying

[jessdgraham]

I recently purchased a Silkie from a lady who told me she had a runny nose. It was my first set of hens to buy so I didn't understand how serious that could be. I put the hen in the coop and now all of my chickens have runny noses and are sucking snot. Theyve quit laying completely and I am worried. I've put antibiotics in their water for the past few days but they are still pretty stand offish. Any advice??