The 'leave' cue teaches your dog impulse control that can be useful in many situations - not to eat food that has fallen on the floor, something your dog finds on a walk, or chase other dogs, rabbits, joggers, cyclists or even a child .
This is important for safety and being a responsible dog owner, it should be taught as soon as your new puppy or dog joins your family.
So to teach 'leave' you need some of your dog's normal kibble, plus an extra tasty treat I use small bits of chicken breast
Hold a piece of food in your closed hand, let your dog know it's there but make sure your dog cannot get to it. In your other hand have another treat ready, it may help to hide it behind your back.
The aim is to get your dog to work out what releases the treat out of your closed hand.
Your dog will sniff, nibble, or paw at your hand, click and reward (the extra tasty treat from your other hand) the moment they look away from your 'bait' hand.
Repeat this exercise a couple of times until your dog consistently makes the decision to look at you instead of the food. You will know you have cracked it when they actively make eye contact in anticipation of the treat coming from elsewhere.
At this stage it’s essential that your furry pal never gets the food that they have been so good in deciding to leave, so the reward now has to come from elsewhere.
Now add the word 'leave' while your dog is in the act of moving his head away. This will build up an association between the cue and the action.
Repeat this process a number of times until saying the word 'leave' results in your dog looking at you instead of the hand held treat they want. click and reward each successful time.
Now that you have built up an association with the word and the behaviour, you can make it harder for your dog.
Put the food on your open palm so that he can see and smell it.
Show your dog the food in your open palm and ask him to 'leave'. At this stage it may be harder for your dog to comply because now they can actually see the treat right in front of them.
If your dog tries to get it, cup your hand over the treat and take your hand away for a few seconds. This gives your dog a clear indication that they haven’t quite figured out what you are asking from them.
If your dog does look away, click and reward.
Rinse and repeat, always finish the session on a high and keep the sessions short and sweet.
Eventually you will be able to reliably leave treats on the floor untouched. Don't forget to practice when out and about too, as soon as you see your dog engage (stiff body posture, staring are common signs) with something of interest, ask for a leave and reward every time. This is so your dog begins to associate things of interest leading to a reward. It strengthens your dog's impulse control and makes other training easier long term.