The deer could have been blind, deaf, and/or sick from the behavior you
mentioned. Deer that are blind/deaf will often seem normal and just on tame
side as they are getting around by scent. Because they couldn't see/hear
dogs, they wouldn't have been alarmed, only curious by the smell. A number
of diseases can also make them act like that in which they are too sick to
care but still not obviously sick for most humans to notice that something
is wrong with them.

Genevieve