hi Kate and welcome..
gotta say, i love to sit on the porch with a cocktail and watch my goofy chickens do their crazy antics too.. of course not now, it's freezing out there..
i'll always have chickens as pets now..
firstly, sorry for your loss..
i'm going with Raccoon.. they are known to eat just the head of chickens.. i catch them outside often.. luckily they are more interested in left over scraps or spilled chicken food on the ground and have never harmed my hens.. i have trapped and relocated some...
female wild turkey that befriended my chickens in the spring.. she would eat their food and take dust baths in the garden with them.. she'd cluck if she couldn't find them.. it was so cute!