It is true that some broodies will quickly adopt chicks on sight and in broad daylight, but best chance for sucess is to always give new chicks to a broody at night. In the case of your newest chick, waiting until tonight also gives the chick time to recover from the exertion spent hatching.
Since your broody has already left the nest with her current chick which she hatched Monday, she may not accept the new chick. That doesn't mean in any way that she is a bad mom; it just means that she sees the new chick as an uninvited, unwelcome intruder and not her own. I would also be very surprised if your other broody that has 1 and 1/2 week old chicks will accept this new chick for the above reason. At their young ages, the chicks of either broody won't mind an additional flockmate, which is why its easy to add additional chicks of younger ages in an artificial brooder. But both your broodies may very much mind. Again, this doesn't mean that either broody is a bad mom. Place the chick behind her tail tonight, well after dark. The chick will instinctively move underneath her for warmth. If the broody seems accepting, leave them for the night. In the morn before dawn, be ready to observe how the broody reacts when she sees the new chick. I hope she accepts the new chick, but odds are probably 50/50 due to the fact she has already bonded to her current chick for 5 days now (or a week and a half depending on which broody you give the chick too. The day old chick may have a hard time keeping up with chicks 10 days older than it, but that is another issue. Good luck and let us know how it turns out.