Several folks I know are having remarkable success with RIR roosters over Shaver hens. You may want to add Shaver's especially if you want to breed your own replacements.
I apologise for not naming names but living in Peka Peka New Zealand I didn't think it would be too helpful. I think the point I was trying to meet is that a poultry breeder whose ingredients are tailored to local conditions and breeds may produce a more targeted product than a commercial...
I have 2 feeds available , one a very well known and very popular quality feed available from the local farm supplies store. In the next town there is a poultry breeder who mixes his own feeds, I note two things, one my hens prefer his feed and they seem to be satisfied with a lesser quantity...
I have found if you want to get eggs all year round then you need a mixture in your flock of Autumn born and Spring born hens however daylight hours do have an affect as well.
There are 2 things that come to mind straight away, firstly the correct ratio for roosters to hens is one to ten so you may have too few hens pariticularily in spring or as young roosters reach sexual maturity. Secondly roosters that act agressively are normaly doing it to protect their "girls'...