To me it looks like the chicks membrane is starting to dry out a bit. There’s a trick in the article about putting oil, coconut I believe, on the membrane to see if the chick has absorbed all of the blood. You will see prominent veining if it hasn’t. If it has then it’s okay to assist as needed.
yes the membrane has dried out. Ideally that egg should be in an incubator to stop is drying out but if that is not an option then warm some water to 100degrees F first then drop a few drops in there. Watch the beak, don't flood the egg but don't just wet a little bit, you need to get the whole membrane wet again, like smiley says it will become more see-through once it is hydrated again
Update ..... The chick wasn't in an incubator but was under my silkie - I didn't intervene and it hatched within a couple of hours after posting this picture and so far is perky and healthy so thank you for your replies - much appreciated and luckily a good outcome so far ...