When to switch mixed age flock to layer?

[newchicksnducks]

I have 3 groups of chicks - 3 at 20 weeks, 7 at 15 weeks, 5 at 12 weeks. None have begun to lay yet. They are currently on unmedicated starter/grower. When should they make the move to layer. I read that too much calcium would not be good for the younger ones. If I offered oyster shell, would the older girls eat what was needed? Or would the younger ones gorge on it? Thanks for any suggestions.

Breeds would be 3 EE, 2 BO, 2 Dom, 2 Black Australorp, 1 Jersey Giant, 2 Speckled Sussex, and 3 GLW (if this makes any difference)

 

[faykokoWV]

I have a similar situation. My decision has been to use a "flock raiser" and offer oyster shell, yogurt and greens to increase calcium in the layers. I have been switching the chicks over when I put them in with the older flock at about 4 weeks old.
There are many different opinions on this, but this is what has been working for me.

 

[aussieheelr]

I switched mine over at 14 weeks. They're doing just fine. Chickens are alot hardier then they're given credit for. So long as you make sure they have their oyster shell they could stay on the chick feed till they lay it is up to you.

 

[warmwater]

I have 3 age groups also.....(6)-6 wk olds...(3)-9 wk olds...(5)-12 wk olds. The 6 and 9 wk olds are on chick starter/grower, the 12 wk olds are on grower/finisher.

When the 9 wk olds turn 10 wks I will put them on grower/finisher. When the 12 wk olds turn 20 wks I will put them on layer.

I know that is a lot of different (age) feed, but each age group has a different protein %. I've read where to high a protein at to early an age isn't good for them.

So, I guess everyone has their own way of doing it. My DH tells me "I'm a little over the top" when it comes to my little ones. It works for me....that is how I raised my older girls and at 7 yrs old they are still laying great.

 

[ThePamperedPullet]

All our chicks go to the large outside pen when they turn about 4 to 6 weeks of age. They start eating layer feed at that point with a bit of starter grower in the morn and eve. The big chickens all think the starter is a treat when we throw it out for the little ones. Haven't had a bit of problem so far. and we handled almost 700 chicks and chickens this past year.