No, hens do not need a rooster around for their eggs to hatch. Hens are capable of laying eggs without any interaction with a rooster. However, for the eggs to be fertilized and develop into chicks, they must be fertilized by sperm from a rooster before they are laid.

If hens are left alone with unfertilized eggs, those eggs will never hatch, regardless of how long they are incubated. Hens will typically lay eggs regardless of whether a rooster is present, but those eggs will only develop into chicks if they have been fertilized by a rooster prior to being laid.

If a hen is sitting on a clutch of unfertilized eggs, she may continue to incubate them for a period of time before eventually abandoning them, as they will never hatch. However, if a hen is sitting on fertilized eggs, she will incubate them for around 21 days until they hatch into chicks, regardless of whether a rooster is present or not.

In summary, while hens do not require a rooster for egg-laying, they do need one for their eggs to be fertilized and hatch into chicks. Without fertilization by a rooster, the eggs will not hatch, even if the hens are left alone with them for an extended period of time.