( I Have 3 other rooms/gourds with 6 each ! 
) But, I HAVE to Really keep an eye on the runt, Which is already WAY smaller than the other 6 ! The oldest is 10 days old & the runt is 4 days old. I ALWAYS tell my other PM friends to NOT Worry about the Runt! They usually catch with the rest of the nestlings, I ONLY do my "Runt Rescue" ONLY when it is BEYOND Clear that it will NOT Catch up with the others ! ONLY then, will I remove them from the nest & put them in a home with 1 or 2 nestlings the same size) I use to let the runts with 5 or more offspring alone to see if they can catch up with the rest, only to find them dead, jumped out WAY to early, & died, or left alone when all the others fledged, & the parents Did NOT return to feed it ! 
) For you newbies, DON't Worry, odds are, your runts will catch up & fledge with the others !
Again, I ONLY do this as a Last Measure to save a runts life, which I'm Happy to say has worked over 90+% of the time, it's great to check up on the "Adopted" New parents home And NOT be able to tell the offspring apart !
& then to find them All have Fledged !