I have heard that hens lay the most eggs in there first year. after that it is a slow decline but can still be adequate for nearly two years. I think this is a question that you will answer when their production no longer meats your needs. Keep in mind that with spiral breeding your are moving roosters from one flock to the next each year. all the while selecting the best for whatever traits you are breeding for. In a perfect world each years breeding will result in a better rooster and hens from each pen. It would in that case be counter productive to keep any of your older roosters or hens for more than one breeding season.
I utilize spiral breeding. Be committed to keeping some records, but this is really a very easy and simple approach:
1. I select best three roos/hens and separate into three groups (if you know by bloodlines/hatcheries/breeders)
2. Maintain these three lines - Line A, Line B, Line C. (I use red/green/blue colors of leg bands to identify who belongs to what line)
3. 1st year breed red roo->red hen, blue roo->blue hen and green roo ->green hen. Simple but understand you must separate the breeding pairs into 3 pens or rotate pairs in succession (first red-14 days later, blue 14 days later green) then you only need one breeding pen. I isolate hens and roo, collect eggs for 7-10 to clear out hen oviduct then consider eggs on days 10-14-6 as the "clutch" to hatch out either by broodie hen or incubator. Mark all clutches by color. All chicks get the mother's color leg band.
4. 2nd yr breed red roo->blue hen, blue roo->green hen and green roo->red hen - got it? follow breeding pen concept above and all chicks get the mother's color leg band. KEEP RECORD.
5. Each year thereafter follow #4 above by rotating different color roo/hen.
Rules:
a. Keep records
b. I always breed 2 yo hens and allow pullets to grow 1 year before breeding.
c. I never breed a single hen more than 3 times
d. I strictly cull hens who have been bred to each color line.
e. I evaluate and select my stock at each breeding pair and replace roosters with sons (same color line) based on who is superior - I use roosters second season old.
f. Everyone else is processed.
If you cannot commit to the strict rigors of breeding (inbreeding/linebreeding/spiral breeding) don't start because you'll end up breeding good animals first year, okay animals second year and frankenstein chickens thereafter.
After tremendous research I've found spiral line breeding to provide excellent layers, table birds, great diversity and improved lines. This is how I plan to maintain a closed flock for many years to come. BTW I breed Blk/Blu Copper Marans and Bresse. I plan to tinker with a Marans/Bresse cross for table birds...maybe.
