It's basic instinct, like your desire to eat when hungry or sleep when very tired. Dogs had to catch small critters to exist until the last century or so and still would if it weren't for human intervention so the instinct is basically survival-based. It can be controlled with a stronger desire to some extent or training. Dogs are led by their sense of smell so if you had a very enticing container of boiled chicken or turkey hot dog chunks by the front door, you might be able to toss several pieces away from the door and get him distracted by the immediacy of food but better maybe better would be to train him to go to a certain spot several feet from the door when you approach it & stay there while it is open, unless you release him to come forward. Tibbe used to be a door-darter but now is trained to go to his "door spot" when the doorbell rings or I go to the door for the mail, etc. He's 97 - 98% reliable but not perfect.
Does he have lots of chances to run and play, get good vigorous exercise and chase balls or have those toys with squeaky things in them to approximate the critter chase/attack? Tibbe has several squeaky squirrels, foxes, etc., that I hold as he chases me and then I throw them, he runs to catch/attack and play-kill, shake hard, etc., and then he leaves them lying all about so he can glory in his critter games wins. He will get up on the couch & survey his "kills" all over the den floor. If I pick them up, they are soon spread all out again so he can see his successes. Such a funny little character. Plus, he chases big birds & squirrels out in the back yard almost every single day so he gets to indulge & enjoy his prey-drive instincts doing that & comes in nice & tired, happy.
__________________  Jeanie and Tibbe One must do the best one can. You may get some marks for a very imperfect answer: you will certainly get none for leaving the question alone. C. S. Lewis |