Can I add my a day old chicks with 2 weeks old ?

[3KillerBs]

Need help identifying these breeds. I am a new chicken owner and I bought the surprise hatchling but later realized that all breeds are different and have different needs. I am going to post a series of pictures and if anyone can help me identify I would appreciate it. Some are 3.5 weeks old and some are 1.5 weeks old. I have narrowed down some breeds but some of the breeds look so familiar it's hard to tell. I know the polish ones, bared Plymouth rock, and Rhode island red but that's about it for certain. Some of the brown ones look like they could be different and some of the black ones as well. Have no idea on any of the grey, black and grey, multi colored ones, and the white wing one. I want to do the best by them so any help would be appreciated.

Welcome to BYC. You would be best off making a thread of your own in the breed and gender section of the forums: https://www.backyardchickens.com/forums/what-breed-or-gender-is-this.15/