Tracking breeding and genetic data

[The_Flower]

What all do you track for when it comes down to breeding and genetic data? Is data tracked via pen & paper, spreadsheet, brain-power? What issues do you face and how do you overcome them? Are there any apps you use specifically that track everything you need to track? I’m looking into starting a breeding program with my French Black Copper Marans and want to make sure I do it well.