broken shell membrane exposed

Hi all

Have a hen that was really broody. Gave her two eggs to hatch out. A few days ago the shell of one was cracked no pips from inside then the next day membrane exposed. Then the hen moved it away and opened it. I found the dead chick with some yoke yet. The other egg was still ok. Yesterday small crack on the egg. Today half the shell on one side gone membrane still soft but worried it wouldn't stay that way. Can see a little movement so I believe chick is still alive. No noise yet. Should I take it from her? I do not have an incubator. This should be day 20 or 21. The egg is from old english bantam and a silkie mix is sitting on it. Should i do something? I am afraid that the membrane will dry out and the chick will die.