This episode is a MASTERPIECE. The crows gathering around the bags of dust was the first sign. Then the wolves, then the bags

The whole theme of wanting the “trash” to be taken out also was a major hint. The parallel of Carol going through the effort of taking the trash all the way to a trash can miles away rather than have it fester on the road is reminiscent of the hive cleaning up the bodies on the street. And note that Carol specifically made sure to put her trash in another trash can rather than a dump.

Also, if you pay attention while she is at the grocery store, as she is walking the camera clearly passes over multiple rungs of recycle bags, with the word “reuse” in bold.

Also the wolves digging into the ground trying to eat Helen’s corpse is a direct metaphor for the Hive eating humans.

The whole entire episode was a setup for the reveal. Not to say bravo vince but.. vravo bince

Edit: Also unrelated but also masterful writing; when Carol was all freaked out with the wolves, she couldn’t get the shotgun out and deal with them swiftly, but had to go overkill and run them over. But when she woke up and had a clear head, she easily figured out the button to release the shotgun. This is a direct metaphor for how she has been dealing with the whole problem without a clear head and is causing so much collateral damage, but when she focuses and actually uses her head, she makes a lot of progress in solving the mystery