Could those have just been other protagonists that Carol saw and mistook for Whisperers?
(If they find a deer that’s wearing another deer’s skin over its own, though, I’m out.)
Or perhaps some kind of animals?
Rarely does a character’s sleep patterns get mentioned on The Walking Dead – which is wild, since everyone should be complaining of insomnia and back pains – so the fact that Carol’s mental weariness and paranoia get brought up so soon after is curious, if nothing else.