Newbee58
Songster
How did you get the chicks? Did you order them? If so, did you order a "straight run"? This will be a mix of hens/roosters (and since the hatchery wants to get rid of roosters it'll be a LOT of roosters).
I don't know what breed(s) you have. Different breeds show different characteristics of male/female bodies at different ages. There are forums on here where people post pics of their birds to have experts look at them and weigh in on the breed. Essentially you're looking for comb/wattle development that looks different depending on if it's male/female. You may also see spur buds on roosters, though hens in some breeds also develop small spurs.
You can always google "picture of 3 month old ___" and see what images come up (though google images can be laughably bad because you never know who labeled that pic).
I got them from a feed store, 5 RIR, 2 barred rocks, 4 EE, 2 Sagitas, 2 Black Auraconda?, 5 golden sex links (know those are female). 5 Bantams. Plus have 3 week olds too. 2 black sex links, 2 more barred rocks, 4 more golden sex links, 2 more bantams. Guess I lost count of how many chickens I had. Lol. Plus I took in a 1 yr old blue laced aundilasion?(not sure of spelling) as person had too many for city ordinances. Which I was surprised she laid eggs 3 out of 4 days we've had her. I thought when they are moved to new environment it stresses them and causes egg production to stop. We got her Sunday afternoon by Monday afternoon we had first egg, then one late Tuesday, none Wednesday and one early this morning. She must feel comfortable here.