I'm partial to Green. He has excellent length and depth and doesn't carry his tail too high. Yes, his comb is a little small but at least it is neat. He looks a bit younger than the others, is that right? Considering he looks that nice at that age, he's quite good. I'm sure his comb will grow.
Blue is too short and his tail is too high.
Now Yellow has beautiful plumage, but look at that wing. He should be carrying it more horizontally.
White looks good but it's hard to tell because the photo is being taken at a different angle. His breast looks very shallow from this angle and is his tail correct or would it be too high in profile? His comb serrations are irregular but it's not too bad. Australorps should have dark brown eyes. Are his lighter than the others or is it simply because he is in the sunlight?