I wouldn't worry too much abou small variations in their poop. If it's soft-ish one day and hard-ish the next, it's most likely nothing to worry about. I can't really tell you specifically what each texture MEANS, but I can tell you Jasper's poop gets a little soft if he gets extra treats or if he gest into something fatty, and it gets hard if he eats a lot of bones.

Things to be concerned about are things that are really unusual, like diarrhea, constipation, or stools that have mucus in or on them. (This does just happen occasionally, but if you see it a lot it can be cause for concern)