If you take a double recessive like caramel hypos, aka caramel glows (gotta use examples I love ) and cross it with a pied clown (just pulling that one outta my head), then you would get nothing but hets. The traits don't change from being recessive to being dominant. If you had caramel hypos and hypo pieds then you'd have eggs that had a 25% chance of being a hypo. The caramel and pied genes would not be expressed.

I think maybe you are just asking if the one trait would show up in an obvious, visual form. And yes, if you have both aa then whatever trait aa is would be expressed in the animal. The nh part would only be het for that trait.

The use of the word dominant doesn't mean it's expressed. It's how the gene behaves in a theoretical sense.

I'm sorry. I don't know why my poor brain is trying to do this in the am. It's not even awake yet. sheesh. *sigh* Maybe that helped, and would someone please put me back in bed.