I just had a similar scenario. I had 3 chicks (2 Wynadottes and 1 Turken) then later decided that I wanted a few more. I added 5 new chicks to the original 3 (then 2 weeks old), 2 Iowa Blues, 2 Welsummers and 1 Golden-Spangled Hamburg. All got along fine after getting pecked on the head a couple of times. No biggie! By the way, I have mine brooding in a 1/2 ton Macro bin.
Thaks Sumi! Sounds like a plan. I would suggest a minimum of 2 new chicks, aged between a day old and 3 weeks. I find that the more newbies that are thrown into the crowd overwhelms the current flock and reduces the amount of pecking that the newcomers recieve. The 3 week old chicks have not fully developed their pecking order and should not be too aggressive toward the babies.
Yes... However, be sure to make sure that everyone is getting along okay, and no one is pecking at the little guy. If they are, separate him and give him the heat lamp. Also give him some gatorade to boost electrolytes through him (since he doesn't have friends to keep him company). Then, slowly introduce him back to the others that were a little older than him. Good luck and sorry about your other little one that died. I feel for ya!