Socialize
The puppies need to be out and about every day and have good novel experiences. Don’t avoid the places Monsters live but…
Pay Attention to Threshold
A threshold is the point at which it is all just too much — stay well under that point with the puppy. When a puppy bites extra hard when taking a treat, refuses to take a treat, and/or is trying to get the heck outta Dodge we know we went over threshold.
Dial it back.
Stay under threshold at all times and…
Counter-Condition
Use treats and fun to help the puppy have a positive association with the Monster — from a safe and below threshold distance.
Puppy looks at the Monster — click/treat (or say YES/treat).
Puppy sniffs the Monster — click/treat (or say YES/treat).
Build up the puppy’s Monster Tolerance, always staying under threshold, until the puppy realizes everything is as cool as the human’s chill attitude.