I'm almost certain it's the former. I have 10 hearts unlocked for my chickens now and I've always just randomly thrown eggs in the incubator.I'm a little confused on how breeding for higher max affection works for chickens since eggs are just kind of... plopped down on the coop and then get stacked in your inventory. Does it just check to see how many chicken generations you've bred so far, or are specific eggs tied to specific chickens and you just have to figure it out yourself