That stupid hawk has been swooping around, so they don't need an open door.
Are you talking about a cat (puss) or the nasty stuff from an infection (pus)? There is probably some weird Latin plural form of pus, or you could use the singular as the plural form (like deer and sheep) when you don't know, because chances are no one else will know either!
Fun fact, if your chicken has pussy eyes, you are saying it has cat eyes! If it has pus in it's eyes, the correct word is purulent. But pussy is more fun!