That's odd, do you have heaters in each barn and coop on your farm, to keep them happy during winter? Make sure you pet all the animals each day!I can get full hearts on certain animals but none on others, and im giving them all the same attention....
This is true! It's more a matter of animals that you let outside will reach full hearts faster when starting from zero. Once your animals are at full hearts, hay and petting each day will be enough to keep them there. But they'll also go through your hay supply faster.I think I remember reading that animals who eat grass and are let outdoors are happier than animals that eat hay. Typically, I let mine roam free so I don't know if that is true or not.