I believe 2yrs old. We received her already grown.
Has she been laying eggs, or in an off-cycle?
I ask because a neighbor's dog got one of my hens, and while she seemed fine for the first couple of days, she went downhill and I realized the dog had broken an egg inside her. She died about 5 days after the attack.
I don't mean to scare you, but some things go unseen, so just something else to consider.