Correct. The eggs will not hatch if the hen is not on them day and night. I'm not sure what you mean by "normally we only have roosters". Do you mean you've had roosters in the past, but no hens? (Your title says you're new to chickens. Do you mean chickens in general, or hens?) It's a little confusing, because roosters are also chickens.
From the picture you just posted, it looks to me like you have 3 roosters and a hen. If that is your only girl, she's going to have a hard time with all those roosters wanting to breed her. I'm not going to quote ratio numbers, but I can tell you that 3 roosters to one hen is way too many roosters.