Being that their is only a few days difference they shouldn't pick on the younger ones. Some of mine are a few days younger that the others and I've not had any problems at all.I have a question too! I'm new at this also! I have 8 chicks, 10 as of Thursday. 3 are about 1.5 weeks, and the other 5 are almost a week. I am getting 2 rooster chicks tomorrow. I have room for them in my brooder I have set up just wanted to make sure the ages were ok. Also the brooder is in my living room. I am using a 250 watt heat bulb right now, and was wondering if I needed to leave it like that because of the younger ones. It hangs at one end so they can get away from it if necessary. Just wanna do what is best for my babies!!!