My voice rang out over the hush of the neighborhood. It was early and as I let Luke and Elsa out for their morning pee, she spotted it first. A rat was in our yard and probably suffering from the effects of poison. The poison is not from me but I know that other people put out poison. I was freaked out that she might touch it so screamed "leave it." To my surprise, she did. Oh it wasn't easy as she was in prey drive mode. Her body was tense and ready. I must have yelled five times; being afraid that she might actually grab it.
Slowly she turned her head; she was still in prey mode. I called her to go and pee which I never thought would happen with a rat sitting there. Very methodically she tip toed away and onto the grass where I told her to "hurry up." She did, and as she left the grass I motioned for her to go inside which she also did while her body and mind remained in the prey zone. What a good girl, that is how a good "leave it" should look. Of course it was much harder than most leave it exercises; this was nearly impossible to leave for her. That along with the fact that she saw it before I did. It is always much more difficult to stop a behavior once it in process.
There are a few things that all dogs should understand. Leave it needs to be taught and proofed. That means you need to practice, practice, practice. Not just under normal situations but weird places like at the park, with very high value items and when they don't expect it, not training time. Clearly Elsa understood by my frantic tone of voice that I meant business, this was a very serious "leave it."
Leave it is very strict in my house; each one of my dogs over the years has clearly understood that when something is dropped it is not a free for all. Dropped things belong to me and if I don't say anything then they will eventually check it out. I was cooking yesterday and dropped a mushroom; it was cooked in butter so Elsa probably would have eaten it. If it was raw, she wouldn't touch it. So as it fell I calmly said "leave it" and she did; then she was rewarded with a piece of meat for not touching the mushroom. This was a much calmer "leave it" than with the rat.
You should be able to ask for a "leave it" at a distance but this takes time. I was quite far from Elsa and the rat when I belted it out. A solid "leave it" means training and it means following up your verbal cue. That means when you say it, mean it. If you allow your dog to take something once you have told them to leave it then you are actually teaching them to disobey you. Think about it.