From the gamekeepers I know that if you can, rear as late as possible. Soggy cold weather really knocks growers, as does wind and those high panel pheasant pens are an ideal answer. Lots of cover to address stress issues (panels on very high grassy area would be ideal) When adult they ought to be allowed a very large area. Reds are fairly easy and standard. You could keep and rear for meat, dressed partridge around her are about £5 per brace.