how is the shared trait between tom walker and his wife shown in the way they collect eggs

Tom's wife would grab the eggs and hoard them the second they were laid. Tom would steal them back when she wasn't looking.

He had a wife as miserly as himself; they were so miserly that they even conspired to cheat each other. Whatever the woman could lay hands on she hid away: a hen could not cackle but she was on the alert to secure the new-laid egg. Her husband was continually prying about to detect her secret hoards, and many and fierce were the conflicts that took place about what ought to have been common property.