The same thing happened to me last week I’m worried I have 3 ducks left and one chicken.what do I do to protect the others
put out game camera so you know what it is and chances are it is either a coon or member of the weasel family.
Rule number 1 have coop and run so no predators can get inside, weasel can thru 1 inch hole..coon can reach grab chickens thru fence if hole is big enough..eat the head.
Rule number 2 remove offending animal if continues to be a problem, but there will be more offending animals which goes back to rule number 1.
The offending animal knows there is a food source, it will return. everything likes chicken
There is many ideas traps, reinforcing coops in reference to predators. If you use the search funtion do some reading I think many of your questions can be answered.
Both weasels , coon climb, dig, chew..at this point you do not know what animal it is.
Sorry for your loss, I have been down the same road.
Good Luck