Here how to breed a pure chooks strain just from Roosters.Example ; Marans. its called " Absorption crossing"
1) Marans Rooster BCM X your hens = F1 50% marans gene.
2) Cross F1 Cockerel ( the one look like a maran phenotype) cross him to his sister/half sister F1 ( maran phenotype ) = F2 in this generation they will be a lot variation in the phenotype.
3) Pick the F2 pullets ( the one that are more marans looking and lay darker eggs ) CROSS them to a pure BCM Rooster = F3 ,they are 75% marans.
4) cross this F3 cockerel to his F3 sisters / half sisters . always go with the marans looking chooks = F4 a litle variation in this generation but not as much as the F2.they still 75% marans genes
5) Pick the F4 best pullets ( marans type) and cross them to a BCM Rooster = F5 they will be 87.5% marans genes.
6) Cross the F5 cockerel to his sisters/half sisters . pick the marans looking chooks = F6 no much variation in this generation by now most of the chooks looks like marans and you will see the one s currying any recessive genes they are a cull .
7) Pick the best F6 pullets and Cross them to a BCM Rooster = F7 this generation will breed true marans
ONE thing is very important is to CROSS the sibling together each type you use a new Rooster. WHY . is to breed out any recessive genes IF you don t do that you will never breed true marans BECAUSE the recessive genes of the original strain crossed to the marans will be passed down.
HOPE that Help
A google search for "absorption crossing" sure doesn't bring much up, just one conversation about cow breeding and your comment here. An FA

Can you point me to any further discussion of this "absorption crossing"?
We could start with where did you get what you wrote from??
Last edited: