¿Cuál es la diferencia entre picky y choosy ?Puedes dar oraciones como ejemplo.

They are pretty much the same, but I think choosy refers more to making a choice, and picky refers to accepting or not accepting something (although, I guess, this is also a choice).
"She has been a picky eater all of her life. If the peas touch the potatoes on her plate, she will refuse to eat either one."
"I hate to go shopping with her. She is so choosy that it takes her 15 minutes to decide which avocado to buy."
"He is so picky about what he wears. I gave him some shoes for Christmas and he has never worn them."
"He is all dressed except for his shoes. He is trying to decide which pair to wear, and he is so choosy that we could be here another hour."
But, in general, they mean the same thing.