Ziggy - you can show anything
- but it all depends how seriously you want to take it and how well you want to do. It's not a cheap hobby so showing anything just for the sake of it is not going to be the best thing as you're likely to get disheartened with the lack of placings etc. But a well chosen puppy from a well bred and chosen litter should be able to be shown without it wasting too much time and money if you know what I mean.
What you can get away with though really comes down to the judge and how well they know the breed standard and what their preferences are in the breed anyway.
Getting the right dog is relatively easy - she says with tongue firmly in cheak, but the hard work is training, grooming and learning how to best show each dog.
Ignoring the breed standard and showing what may be a lovely pet but a mile away from the standard - say a neutered fully clipped Cocker will not go down well with the judge as they will feel you are wasting their time.
But with a reasonable amount of effort you can have enough success to make it an enjoyable hobby. Choose your shows carefully and set your expectations to a reasonable level and it can be great fun