Duration of Heats

I know that wolves are in heat for 4 days and pregnant for another 4, but I wondering about how this is displayed. For example, some of my wolves are said to be "In Heat (1 day)" or "In Heat (1 rollover)", but I thought that they started out saying "In Heat (3 days)". So tomorrow after rollover, will they say "In Heat (0 days)", or will they no longer be in heat? Thanks!

It will be 'in heat for 0 rollovers' :) So the wolf is in heat for 4 days (3 rollovers) and will go out of heat on the 4th rollover (end of the 4th day). 

Wonderful, I just wanted to make sure - thank you very much!