I'm sorry you're feelin' so bad, but ... hopin' you'll read back over my last post, 'n reconsider how you look at such losses. It is hard, most esp. when we feel it's due to our own error, but you need to remember that you gave it far more time, love and attention than most chickens ever get...
Although it's only the most evil among mankind that culls those that they perceive to be less than the 'ideal' person, we also don't have 'human nuggets' or 'people noodle soup' on any menu I've ever seen ... be prepared to face severe financial and emotional hardships, should you attempt to...
As to the potential for Marek's? Certainly ... there doesn't need to be any historical events, or potential for entry, as it's sorta like Parvo w/in canines: You walk, hop in the car, go somewhere, hop back in, and it accumulates on your shoes, in the carpet, etc. And, just as you see evidence...