The choice of treats are definitely very important in the world of clicker training. First and foremost, the treats must be something that the dog really likes. Secondly, the treats should be small, pea-size or slightly bigger for a large-breed dog and smaller for a small/toy breed.
I have found when training rottweilers and german shepherds that if the treats are too small, the dogs invariably choke on them. If they are too large, you simply run out of treats before you are really finished training. I tend to treat generously and often, so that is a big issue for me.
When training toy breeds, like pomeranians, if the treats are too large, the dogs will fill up quickly and you will have to either find an alternative to food as a reward, or quit training for that session. I have never had this issue with my large dogs, so I can’t swear that it won’t happen to larger breeds.
Treats should be smelly and soft. If they are smelly, they will be palatable to the dog; if they are soft, the dog will be able to eat the treat quickly and not disrupt the training session. I store my treats in a zip-lock bag to seal in moisture and stuff it in my treat bag (which is nothing more than an insulated lunch sack for humans which I clip to my belt when I train). When I’m finished training, depending on the treats, I store the zip-lock bag with any remaining treats in the refrigerator.
Because my dogs tire of eating the same treats over a long period of time, I tend to add variety. So for several days or even weeks I’ll train using bits of cheese, then I’ll switch to bits of sausage, then pieces of boiled liver. I have found sausage (hotdog) to be very messy as the links invariably retain lots of moisture, especially if you thaw them then serve.
Unlike many trainers, I do not mix treats within a training session. It’s just too much work and gets cumbersome to manage during sessions. Timing is important in clicker training, so you don’t want to be fumbling with getting the treats out of the pouch, especially when training an inexperienced or young dog.
Of late I’ve been using commercial treats for variety, especially for Athena, who is not a food oriented dog. One of the treats, Scoops made by Seargent, is supposedly made with real cream. It is a soft treat and breaks into small pieces very easily and are not nearly as messy as sausage. I just started using Beggin’ Strips, too. I like these treats because they are the least messy of all. I can push a few strips in my pockets and not worry about messes. Although they break up quite easily. I have found that the dog needs some time to chew the treat during training, and depending on the size of the dog, if the treat is too small, the dog has a hard time chewing it.
Bottom line is, choose food that your dog truly enjoys. The reward must be of a high value to the dog. If the food isn’t something that the dog particularly relishes, then the very act of offering a treat becomes an aversive.