I had a similar situation when I got my chicks. My first batch had a lot of fatalities and the company sent me new ones the following week. I just cut a piece of hardware cloth and taped it up and left them separated like that for a few days. That way they could see each other and it was fine after that. Otherwise it would have been disastrous! When I was putting them on the other side the other bigger chicks were jumping all excitedly and I just know they would’ve attacked them. One week makes a lot of difference in a baby chick size wise.I can’t remember exactly but I think I just left the wire up in the brooder for maybe three days.I have 8 mixed flock chicks that are 1 week old today. My neighbor ordered 5 new chicks after a disastrous order last week and they will be arriving tomorrow. If all of them come alive, she will be giving 1 to me as she only wants 4. I am happy to take it but I do not have a separate area for this chick and will have to integrate it right into my current flock. Any tips? Is this a disaster waiting to happen or am I being overly concerned?