Would depend on your area. Wouldn't want to take her out of the coop area if your yard is not fenced in to keep other predator away or if you have other animals where she may find other eggs to sit on. Broody hens don't care who's eggs they sit on or golf balls, rocks, LOL.
The best way I have found to break a broody hen is to put her in a pen off the ground for a few days. Wire bottom pen. That always seems to break them for me.
I've seen it around my fence from time to time and I get rid of it any chance I get, but have never had an issue with the chickens, ducks, or turkeys I have had. Although I don't feed it directly too them.
My son has an electric netting fence that does touch the ground and it is solar powered. So far he is very happy with it. It was an amazon purchase. I don't know the brand name but they do exist.
I see a couple in the mix of photos that seem to be showing more red in their combs and the combs seem to be a little larger as well. I'm guessing future roos.
The black and gold one looks to be a roo ro me. It has pointed feather near the base of the neck and the crest appears to me to be that of a roo. From the pictures the others look like they could be pullets, but some of them are at a bad angle in the Pic to say for sure.
I would keep the sex link roo. My reason would be if you did decide to hatch chicks you might be able to add the egg production qualities into the flock that maybe the sex link could bring, but I'm no expert, just a thought.
Yes, I know it's early. They just all have all seemed to be developing at the same speed, as far as tail feathers go. Everyone has them. Usually the roos appear to be late bloomers in the tail feathers category. LOL! I meant to add that they are 3 weeks old.
What's the chance? I think my bantam St. Run is looking like all pullets. I ordered bantam RIR and some bantam EE. Just for fun, eggs, and maybe showing the bantam RIR. I was planning on hatching eggs from the flock and so far I'm not seeing any sign of a roo in the bunch. All have little tails...