This guide describes a easy cheat to get full hearts with any NPC.
1.) Buy a coop
2.) Buy a chicken and name it
#$actio${^^
}$n Add${^^
}$Frien${^^
}$dship${^^
}$Point${^^
}$s Sha${^^
}$ne 10${^^
}$00000
This cheat will gain you 1,000,000 friendship points with Shane. If you want less or more friendship points or replace Shane with another NPC, you can adjust that. The cheat code should be copied and pasted as the new chicken’s name exactly in the format in which it is written here (with the breaks and all the special characters).
Just use the format above. It should contain up to 5 symbols between the }$ and {^^.
For instance the cheat for Pam would be:
#$actio${^^
}$n Add${^^
}$Frien${^^
}$dship${^^
}$Point${^^
}$s Pam${^^
}$10000${^^
}$0
When you buy the Chicken, Marnie will give out the cheat code and you should immediately gain the friendship points with the desired NPC.