My three hens are almost five years old now and are laying only a few eggs a week combined, and that's dropping even more (to maybe 2 a week combined) now that it's getting colder. I'm really into nutrition and I'm wondering if anybody knows of any special nutrient requirements for older hens. I doubt there's any "senior" feed like for other livestock, but has anybody tried anything for holder hens? One thing I worry about is whether too much calcium could start causing problems, since they aren't using it to make egg shells like they used to. Right now I feed them a complete layer feed and supplement it with oyster shells and treats. Thanks!