I am currently trying a broiler/laying-hen mix. The broiler being some sort of white CX but maybe not the very fast growing kind. The two roosters I kept for breeding were 3kg (+6.5lbs) and 4kg (8.8lbs) clean (skinned, all innards out, feet off), when I processed them around six months of age. I did restrict their feed and they managed to forage quite well. They did mount the hens well and started crowing around 4 months of age.
The laying-hen being an isa-brown I would imagine.
The plan was to get some faster growth in my brahmas but that didn't work out as hoped, big rooster did not fertilize one egg, smaller rooster did take with a small brahma. I ended up putting 6 extra eggs (isa-brown) in the incubator because I had the space due to lack of brahma eggs.
The six (F1) turned out 4 boys and 2 girls. Big difference in growth between the six. I kept the best rooster and both hens. The faster growing hen started laying at 4 months (from mid-summer last year, all through the winter, had a two week stop in March and been laying again since then).
The smaller hen was well over six months when she started laying (nearly seven I think), and still well behind her sister in development. She has caught up by now and surpassed the fast-grower in size.
Egg size was consistently around 80 grams all through winter, but has gone down now (around 70gr and less). I should add we had no snow this year and hardly any frost.
When I butchered the rooster (F1) he was 3kg clean at 11 months.
I've had three F2 rounds hatch. I'm having fertility and hatching problems. Last round I put in 24 eggs, of which 8 were unfertilized, 8 didn't make it out of their shells and 8 hatched. Of those 8, one died after a day and one had a bad leg. The six that are left are doing very well and are extremely active.
I butchered the first F2 cockerel at almost 20 weeks. I'm selecting on broadness first, this one was narrow so had to go. One thing that stands out is that some are very narrow, especially the pullets. They seem to fill out though as they get older, the roosters are being processed before they get there. I'm keeping the widest to continue.
Even though this cockerel was so narrow, he was quite meaty, especially in chest meat. He was 1.2kg (2.6lbs) clean. Taste wise, this one was as good as it gets, and not at all tough at nearly 20 weeks, he was fried slowly in a saucepan for half an hour. But taste is very subjective, I like the brahmas in a coq au vin but not any other way for example.
The reason for trying this is that it's been getting increasingly harder to buy meat-chicks. We used to be able to just go to one of the weekly markets around the area and buy whatever. The last few years markets in general (covid now) and poultry specifically are being restricted. Every year there's some bird-flu going round that calls for prohibiting the sale and transport of poultry (!?). Even when there's no restrictions it's sometimes hard to get your hands on fast growing meat-chickens.
So, the goal is to have something that lays a decent amount of eggs, for eating and hatching, and that doesn't eat like a docker but still puts a decent amount of meat on in a reasonable amount of time, 20 weeks would be ideal.
For numbers, as a bit of a guiding goal that might change as I go, I want around 200 eggs a year for the hens (I'm way over that for now, looking at 300+ if they keep going the way they have) and an average 2 kg (preferably more but will have to see as I go) clean carcass at 20 weeks for the cockerels.
The plan before winter was to breed F1 to F1, F2 to F2, and so on for 5 generations to get the type I want right, and then start worrying about other aspects.
I have changed that plan as I'm in no hurry (they grow ok, taste good and lay great) and don't have the space to keep 3 or 4 separate coops for the spiral breeding method.
I will be keeping my F1 hens and the best (broadest) hens of successive generations. I will pick one or two roosters to breed with all the hens and process them when their second batch of offspring hatches. This way there will always be an aunt and great-aunt they breed with. I'm hoping to keep inbreeding problems low this way. If I'm missing something, please feel free to correct me, I've had chickens for over forty years but my breeding experience and genetic knowledge is very limited.
With the brahmas I had a hatching rate of +80% and sometimes even 100%. They did make it out of the shell but some of them were very weak and I ended up culling them over time anyway.
I'm at 33% hatching and 25% surviving and growing well with my last batch of broiler/layer. I think the hardness/thickness of the shell has something to do with it, the brahma shells are markedly softer/thinner. They all get the same food.
If I can get that up to 50% surviving and growing well to butcher or egg-laying age, I think I should be doing ok. Natural selection should do that for me where the shells are too thick if that's what's going on. Any thoughts on this matter are also very welcome.