Similar to Origins I've found some red colored dig spots only visible in zombie blood mode

The locations I've found so far are:
~ Mound of rocks on the side opposite of the well
~ In the back corner of the graveyard
~ In front of the parlor
~ Across from the box spawn at the Hotel
~ In the corner to the right of the barn
~ Next to the Winchester Model 94 wallbuy
~ To the right outside the Saloon Entrance
~ Behind the Saloon, directly out the back door

Any other locations would be lovely to know.
(Note, there were all found in one game)