Rooster got hurt

[Eggcessive]

Chicken probably, but I will check on it. For raccoons, I use Snickers or canned tuna.

 

[Eggcessive]

There is a weasel bait for sale through Walmart and online. But fish, chicken, liver , and chickens entrails are common bait. Here you go:
http://www.havahart.com/weasel-baits#baits

And an article with advice on trapping:
http://www.havahart.com/how-to-trap-weasels

 

[50-45-1]

I am sorry for the loss of your birds.
If you have a weasel please know they can squeeze through a 1 inch hole, about the size a mouse can fit through. I would not put any more chickens in that coop until you give it a complete overhaul.
A mink would need a larger hole softball size.
In all the years i have had chickens i have had 2 weasels. I traped them the next night using a small have-a-heart trap and a piece of a chicken that it had killed the night before as bait. You wire the bait on the pan so the critter has to work to get it, setting off the trap.
IF your coop has one small flaw, these varments will find it and once they have found a fresh meat source, they keep coming back.
I am sorry for your one remaining hen, she will be lonely until the chicks get bigger. Dont put them together until they are bigger and can outrun her. She may not be very nice to them. Do alot of supervising at first.
It would be nice to see some photos of your coop at some point before you put more chickens in it.
We are here to help.
My last weasel below. He got onto my coop by following a mouse tunnel that had found a way under the hardware cloth i have burried a foot deep in the ground surrounding my coop. He killed 3 adult birds, one my broody hen who had 3 chicks about 3 weeks old. He killed them too.

 

[RiChicken420]

I haven't caught the critter but put my hen in the basement today don't wanna risk it till I went over every nook and cranny of the coop so you think it a bad idea to house the old hen with the chicks I ordered

 

[50-45-1]

If a hen is broody she may accept day old chicks.
Otherwise she will likely peck them to death.
No, dont put them together. Not until they are months old and big enough to escape her if she is aggresive twords them. Integrating different age chickens can be challenging.