You can do what you wish. There is no chicken police going to come around and fine you or throw you in jail. I’ll try to give you some information that may help you decide what you want to do.
Here are links to two different studies about feeding nothing but Layer to chicks. In one study they start feeding Layer at hatch, in the other they start that at 5 weeks. In both they not only count how many extra chicks die when fed nothing but Layer, they cu the chicks open to look at the damage caused to internal organs by feeding them nothing but Layer. The conclusion of both studies: Don’t feed only Layer to young growing chicks. The extra calcium in Layer can kill them or cause permanent damage to their internal organs.
Avian Gout
http://en.engormix.com/MA-poultry-i.../avian-gout-causes-treatment-t1246/165-p0.htm
British Study – Calcium and Protein
http://www.2ndchance.info/goutGuoHighProtein+Ca.pdf
A couple of things about these studies. One bite won’t kill them. It’s not about what percentage calcium in a few bites of what they eat. It’s about total calcium they eat in a day. If they get most of their food from foraging or from other low calcium foods, then a few bites of Layer is not a problem at all. And it’s not about what they eat in one specific day. And the damage is cumulative. They have to eat excess calcium every day for a while to cause the damage. In these studies, they eat nothing but Layer every day. If a broody keeps her chicks out foraging for practically all day and they only eat a few bites of Layer, that amount of calcium is unlikely to hurt them.
They don’t need 24% protein Starter or 20% combined Starter/Grower until they start to lay and you switch to Layer. You can feed that to them if you wish but they just don’t need it. As the recommendations say, they are fine on 16% Grower after 4 to 8 weeks until they switch to Layer or a 15% Developer/Finisher from about 13 weeks until they switch to Layer.
The 24% Starter is $3.00 per 50 pound bag more expensive than a 50 pound bag of 15% Finisher/Developer at my local
Tractor Supply. The 20% combined Starter/Grower is $2.00 per bag more expensive than that Developer/Finisher. If you want to spend the extra money for something they don’t need, that is your choice. I don’t have a choice for a straight 16% Grower so I don’t have a price.
It’s a free country. If you want to feed them Layer when studies show it can harm them, go for it. If you want to spend extra money to feed them, that doesn’t hurt my feelings at all. They are your chickens, not mine, so that is your business.