I know how you feel, last year almost all my birds were decimated by coons, raptors, rats, vehicles...you name it. Even got by accident medicated feed that we didn't realize was medicated and it killed off a bunch of them. You have my sympathies!
Are they getting in via any holes in the coop? Or are they killing them during the day? Are they digging under the coop?

They were getting in every way they could, they were climbing up the side of the coop and squeezing through a tiny space, I can't believe they got in. You need to fortify your defenses. If they're digging in, you need to put down a cement floor. That helped with us, it's a pain in the butt but it will keep them out. You can mix in some dirt with the cement to let it go farther (source Gail Damerow's "Guide to Raising Chickens", Storey publication).

We were down to 3 hens and 3 cocks, 8 guineas and 4 ducks. It was a bad year last year. I'm sorry you are having such a bad time of it!

Oh, update. Since I last posted my comment, we had another raccoon find a soft spot in the wood and ripped it apart and killed 4 guineas and one duck setting on a nest. We got the havaheart trap and got the bugger, and I made my first raccoon pot pie, and it wasn't too bad, especially the second day.

Sorry to hear about your loss! As my title says...I HATE RACCOONS! I caught all of them for now, but it took me a week to get them.

We had a 4th of July party / bonfire Saturday night. My bonfire location is about 100' from my barn and coop. We were all sitting around the bonfire around 11:30 pm having a few beverages when I look up and see a coyote walking up to the coop like he didn't have a care in the world. I started screaming at it and it stopped and looked at me like, "what you going to do about it?" I didn't have to do nothing...my dog (who is very protective of his little patch of dirt) was on him in seconds. My oldest son pulled Jensen (the dog) off long enough for the coyote to get away and my dog didn't get hurt...which would have been inevitable.

I have lived in the country all my life and have never seen a coyote be that brazen. Times are changing...

As far as updating the coop...it has been this way for 30-years. My experience tells me that a coon, rat, bird, coyote, etc will get your livestock if they want it bad enough. Just like a thief...if he wants in your house or car, he is getting in. All the locks do is keep honest people honest.

I am not going to spend thousands of dollars trying to keep them out. I have chain link fence for the coop and hog panels with chicken wire at the bottom for the run (no roof on run). I loose chickens when I forget to close the coop door at night. I lost my chickens because I let the weeds grow up in the run. The dead carcasses where hidden in the weeds where I couldn't see them. Since I have been shutting the door and setting out the live trap...all is back to normal.

I'm very glad to hear your dog didn't get bitten or worse by that coyote. If they aren't hunted around an area that could make them brazen. We never had coyotes around here until recently, but I only caught a glimpse of one, it was like the shadow of a ghost, gone in a nanosecond. I wonder if the coyote had distemper or (gulp) rabies to make it act like that? We had a rabid raccoon one time around here, it was trying to get into the house in broad daylight. We also have bears around here and mountain lions, but they try to keep hidden.
I love those havaheart traps, they sure do help. You should try raccoon pie, though it's a pretty gamey meat, most gamey I've ever tried. I like woodchucks a lot more.