Can they perch yet? They are about 5-6 weeks old and have their wing feathers and some of them are light breed and fly well but I do have some heavier breeds like buff orpingtons wyandottes and delawares. 
I’ve seen a broody hen take her chicks to the roosts at 2 weeks of age.  They flew up 2’ and horizontal 3’ and could have easily gone much further.  These were heavy breed chicks.  They roosted on the roosts, so yes, 5 to 6 week old chicks can perch.  The question is, will they?
Perching is when they park themselves somewhere up and sit there.  Extremely young chicks will do that.  Roosting is when they spend the night on some kind of roost.  I think roosting is what you are talking about, not just perching.
My brooder raised chicks often perch during the day before they are a full week old.  It’s fun.  My brooder raised chicks usually start roosting at 10 to 12 weeks of age if I leave them alone.  I have had some start roosting at 5 weeks on their own, I’ve had some take a lot longer.  The 10-12 weeks is kind of an average.  If they are in the main coop with the adults, they usually don’t roost on the same roosts as the adults until the pullets start to lay.  Until then they are afraid of the adults.
Also should I put them near the grown chickens? 
I’m a big proponent of keeping them near the adults.  It helps tremendously with integration.  There are a lot of different opinions and experiences posted on this forum about how and when to integrate, but I find it hugely beneficial if they are housed next to each other so they can see each other.  
And we do have water snakes that are pretty good size will they attack the chicks? 
Snakes will eat chicks, depending on the size of the snake and the size of the chick.  
We do have dogs so should we put them near them so they can scare off cats or other things? 
Dogs are an interesting topic.  They certainly can be a deterrent to many predators.  To do that, they have to be in the vicinity when the predator shows up.  If you lock your dog in the house at night when predator attacks are most likely the deterrence is pretty close to zero at night.  Practically any predator can possibly attack during the day, but night is when most are more of a danger.
The flip side is that dogs are probably the worst predator to chickens there is on this forum.  They are at least near the top of the list.  Most dogs can be trained to not harm the chicks and chickens, but it takes training, especially when the chicken runs away from them.  If you try to use dogs, train them or make very sure the dogs cannot get to the chickens.  That included digging under a fence.
Also I'm kind of worried about worms or other parasites how can I prevent that? 
Parasites are either in your environment or they are not, though they can be brought in.  If they are in your environment you can’t prevent them unless you keep your chickens under commercial operations biosecurity conditions.  You probably don’t want to do that.  
The presence of parasites is not a death sentence.  Animals can handle a certain parasite load without any real harmful effects.  It’s when the numbers get large that it normally becomes a problem.  Your goal should first be to prevent it if you can, but if they are present, keep the numbers under control.  
One of the best ways to prevent is to not let your chickens come into contact with other chickens.  That’s called a closed flock.  Don’t bring in other chickens or take your chickens to other chickens, like at chicken shows.  Don’t wear the same clothes to feed stores or chicken shows that you wear to manage your chickens, you might track in something.  That’s especially true of shoes.
I introduce my chicks to the environment they will live in at a very early age.  That helps them work on flock immunities and builds a stronger immune system.  One thing I do is feed them dirt from the run to get the flock immunities started off when they are just a day or two old in the brooder.
One way to minimize the numbers of certain things like worms to build up is to give them as much space as you can or manage the poop so it doesn’t build up.  The higher your chicken concentration the more the poop is likely to build up.  That’s a common way for internal parasites to build up.  
That’s about it for me.  If you see parasites, treat for them.  If you see them they have probably built up their numbers.  Some people treat for parasites regularly, whether they see them or not.  I don’t, I believe in only treating when I have a problem to treat.  
For what it’s worth, I’ve had chickens here for 9 years.  I butcher a lot of my chickens.  Whenever I do, I split the intestines open and look for worms.  I have not seen one yet.  I regularly check for mites and lice.  I have not seen any yet.  I do have a strain of Coccidiosis in my soil, I had chicks get sick once.  But by feeding them dirt with that parasite in it while they are in the brooder and keeping the brooder dry and the water clean, they develop the immunity they need against that strain before they hit the ground.  
Good luck!