A farmer crosses a black rooster with a white hen of the

Question

A farmer crosses a black rooster with a white hen. Of the seven offspring, three are black, three are speckled black and white, and one is white.

1. How do I find what I could infer about the black and white alleles?
2. How do I create the ratios of characteristics among the offspring? 
3. What further information would I need in order to draw conclusions about the inheritance of this trait?