It's cool and rainy here right now, as long as the hen is sitting and taking care of the chicks, do I need to put a heat lamp in there with the chicks?
You do not need a heat lamp when you have a broody hen. Do not put a heat lamp in there, now or later.
As far as food goes, do I just set a separate chick feeder in there? Do I need to keep the regular layer feed the hen eats up and away from the chicks?
You will find it impossible to keep the baby chicks out of Layer if you try to feed both. The broody hen will pick it up and feed it to them if they can’t get at it. In a surprisingly short time the chick swill fly up there to eat it themselves. Mine regularly do that before two weeks of age. A standard way of feeding a mixed age flock like that is to feed them all what the chicks can eat and offer oyster shell on the side. The ones that need it for egg shells usually know they need it. The ones that don’t need it don’t eat enough to harm themselves.
Medicated or non-medicated feed for the chicks?
Purely personal choice. I’ll copy something I wrote on another post about this. It’s kind of long but may help you make an informed choice.
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. Every "medicated' feed I'm aware of from major brands for chicks that will be layers uses Amprolium, but people on this forum that I trust have posted hat some feeds for broilers have things other than Amprolium. I'll assume it 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.
Any other special things that I need to know before I hit the feed store after I get off of work?
I understand it’s your first broody and you are excited. You want everything to go perfectly. One thing I’ve learned about broody hens is to leave them alone. Stay out of their way. Don’t try to micromanage them, they know a lot more about it than I do. I know it’s hard but try to not interfere too much. If you put food and water where the chicks can get to it, the hen will do everything else.