When can I expect the females to start laying? I've read that the sex-links will start earlier?
When you see an egg. I've had pullets start to lay as early as 16 weeks. I've had some not lay their first egg until 9 months. Each pullet is an individual
Yours are not really breeds, they'd be considered more to be types. On average they tend to start fairly early but that is an average. You have to have enough for averages to mean something and you don't. They are living animals not programmable bots as some people on here might have you believe. Some are going to start pretty early, some fairly late. Most somewhere in the middle. I don't know if you have an early one or a late one.
When should I open up the laying boxes for them? Right now I've got the boxes blocked off in the coop so they don't sleep in there.
Before a pullet starts to lay she often looks for a good place to make a nest, maybe a week before she starts. If your nests are closed to her when she is looking she may never even consider your nest as a good place to lay. By leaving them closed you may be teaching them to not lay in your nests.
Where are yours sleeping now? Are they still sleeping on the floor or on the roosts? If your roosts are higher than the nests they very rarely sleep in the nests once they start roosting. If they are still sleeping on the coop floor and your nests are on the coop floor they may try to sleep in those nests until they start roosting. So if your nests are on the coop floor and they are still sleeping on the coop floor, you might want to wait until they start roosting or train them to roost now. If they are already sleeping on the roosts open the nests now.
It is possible they will try to sleep in the nests even if the roosts are higher. If they do sleep in the nests there is a reason. I want to know that they are sleeping in the nests so I can fix that before I start to get poopy eggs. If you open the nests and they start sleeping n there get back to me so we can start working on how to fix that problem.
I'm currently feeding them Purina medicated start and grow crumbles. When should I switch them to a more adult food, and what should I switch to?
This can be a very long answer, there are so many different parts to it and you have a huge amount of options. At the end of this I'll copy something I wrote about medicated feed. Read that and get back to me with any questions but basically you can switch any time you want.
What should you switch to? Many options. Growing chickens should not be fed a feed with the amount of Calcium that is in Layer. It can be harmful to internal organs or their skeleton. I almost always have immature chickens in the flock. The way I handle this is to never feed Layer. I feed a low calcium feed like Chick Starter or Grower and offer oyster shell on the side. The ones that need the extra calcium for egg shells seem to know it while the ones that don't need that extra calcium don't eat enough to harm themselves.
We all have different types of low calcium feeds we use. I generally start off with a 18% Starter until the chicks are 4 to 6 weeks old (whenever that feed bag runs out) and switch to a 16% Grower. All chickens, hens, rooster, and chicks get the same thing. Some people use other feeds, maybe Flock Raiser or All-Flock. These are just marketing names and can vary a little in amount of protein. There is a lot of personal preference in what we use. My preference is a slightly lower protein content, some people like a higher percent protein feed.
This is the write-up on medicated feed I mentioned.
First you need to know what the "medicated" is in the medicated feed. It should be on the label. Usually it is Amprolium, Amprol, some such product, but until you read the label, you really don't know. Most "medicated' feed from major brands for chicks that will be layers uses Amprolium, but there are a few out there mostly for broilers that use other medicines. I'll assume yours is an Amprolium product, but if it is not, then realize everything I say about it may not apply. And it is possible that the "medicated" is Amprolium AND something else.
Amprol is not an antibiotic. It does not kill anything. It inhibits the protozoa that cause coccidiosis (often called Cocci on this forum) from multiplying in the chicken's system. It does not prevent the protozoa from multiplying; it just slows that multiplication down. There are several different strains of protozoa that can cause Cocci, some more severe than others. Chickens can develop immunity to a specific strain of the protozoa, but that does not give them immunity to all protozoa that cause Cocci. Little bitty tiny baby chicks can develop that immunity easier than older chickens.
It is not a big deal for the chicken’s intestines to contain some of the protozoa that cause Cocci. The problem comes in when the number of those protozoa gets huge. The protozoa can multiply in the chicken’s intestines but also in wet manure. Different protozoa strains have different strengths, but for almost all cases, if you keep the brooder dry, you will not have a problem.
To develop immunity to a specific strain, that protozoa needs to be in the chicks intestines for two or three weeks. The normal sequence is that a chick has the protozoa. It poops and some of the cysts that develop the protozoa come out in the poop. If the poop is slightly damp, those cysts develop and will then develop in the chick's intestines when the chicks eat that poop. This cycle needs go on for a few weeks so all chicks are exposed and they are exposed long enough to develop immunity. A couple of important points here. You do need to watch them to see if they are getting sick. And the key is to keep the brooder dry yet allow some of the poop to stay damp. Not soaking wet, just barely damp. Wet poop can lead to serious problems.
What sometimes happens is that people keep chicks in a brooder and feed them medicated feed while they are in the brooder. Those chicks are never exposed to the Cocci protozoa that lives in the dirt in their run, so they never develop the immunity to it. Then, they are switched to non-medicated feed and put on the ground where they are for the first time exposed to the protozoa. They do not have immunity, they do not have the protection of the medicated feed, so they get sick. Feeding medicated feed while in the brooder was a complete waste.
I do not feed medicated feed. I keep the brooder dry to not allow the protozoa to breed uncontrollably. The third day that they are in the brooder, I take a scoop of dirt from the run and feed it to them so I can introduce the protozoa and they can develop the immunity they need to the strain they need to develop an immunity to. To provide a place for that slightly damp poop, I keep a square of plywood in the dry brooder and let the poop build up on that. I don't lose chicks to Cocci when they hit the ground.
There is absolutely nothing wrong with feeding medicated feed to chicks, whether the protozoa are present or not. It will not hurt them. They can still develop the immunity they need. But unless the protozoa are present, it also does no good.
If you get your chicks vaccinated for Cocci, do not feed medicated feed. It can negate the vaccinations.
If I decide to cull and cook my cockerel, what age is best to do this?
Another question with no simple answer. We all do this differently for different reasons. The age they are butchered can have a big effect on how you should cook them. The older a cockerel gets the more flavor and texture they develop. Some people like that flavor and texture, some don't.
Some people butcher at 12 weeks, trying to get them before puberty hits and they start harassing the girls or before they start to crow. There is very little meat on a 12 week old however. Some more popular ages are 14 weeks and 16 weeks. My preference is 23 weeks as that suits my goals, how I raise them, and how I want to cook them. Some people wait even longer.
I find with chickens that there is no one way that is best for every person on the planet. There are many different things that can work. What works for me may not work for you. Our personal preferences and our unique circumstances might make one way better for me than for you.