What are the best ways to introduce 8 week old chicks to my flock that are about 13-14 weeks old?

[Shalai]

It's time to evict my last bunch of chicks. I have 5 of them. They are about 8 weeks old. My flock already outside has 10 chicks and they are 12-13 weeks old. They are just so much bigger than the babies. You wouldn't think 4 weeks makes such a difference! I can separate them during the day in the run, but both runs are attached to each side of the coop.

 

[aart]

How big is the coop, can you split it in half?
Dimensions and pics of coop and runs, inside and out, might help garner viable suggestions.

Meanwhile here's some tips about.....
Integration Basics:
It's all about territory and resources(space/food/water).
Existing birds will almost always attack new ones to defend their resources.
Understanding chicken behaviors is essential to integrating new birds into your flock.

Confine new birds within sight but physically segregated from older/existing birds for several weeks, so they can see and get used to each other but not physically interact.

In adjacent runs, spread scratch grains along the dividing mesh, best if mesh is just big enough for birds to stick their head thru, so they get used to eating together.

The more space, the better. Birds will peck to establish dominance, the pecked bird needs space to get away. As long as there's no copious blood drawn and/or new bird is not trapped/pinned down and beaten unmercilessly, let them work it out. Every time you interfere or remove new birds, they'll have to start the pecking order thing all over again.

Multiple feed/water stations. Dominance issues are most often carried out over sustenance, more stations lessens the frequency of that issue.

Places for the new birds to hide 'out of line of sight'(but not a dead end trap) and/or up and away from any bully birds. Roosts, pallets or boards leaned up against walls or up on concrete blocks, old chairs tables, branches, logs, stumps out in the run can really help. Lots of diversion and places to 'hide' instead of bare wide open run.

Good ideas for hiding places:
https://www.backyardchickens.com/threads/a-cluttered-run.1323792/

 

[Ridgerunner]

How big is your coop, in feet or meters? How big are your runs, in feet or meters? Photos showing how they are set up and of the inside of your coop could be very helpful in us understanding what you are working with.

It is possible you could just put them together and they will get along. That actually works sometimes, especially if you have a lot of room. By get along, I mean they don't try to injure or kill the younger ones. That does not mean they cuddle up to each other or eat and drink together. I don't mind them staying far apart as long as they don't hurt each other. But sometimes even when they are that far apart in age and size they act as if they have been together all their lives. You never know how they will react until you try.

Sometimes that does not work, especially if room is tight. I can give generic suggestions but without detailed knowledge of what you are working with I cannot get specific.

You have two different problem times. During the day it is normal for the young to stay away from the older. You basically see two different flocks where the young move away if the older group moves toward them. They need enough room to move away. It also helps to have widely separated feed and water stations so the young can eat without having to challenge the older ones. This takes room, especially outside. I have no idea how much room you have.

At night my younger chicks do not sleep on the roost with the older chickens. If your coop is big enough and the roosts are set up so the chicks can sleep in a back corner away from the others they may try that. Most of us do not have coops and roosts that big. My younger chicks either sleep in a group on the coop floor or find another place to sleep away from the older ones. As long as that is not a nest and is somewhere predator safe I don't care where that is. To keep them from sleeping in the nests and leave my nests open for my adults to lay in I installed a juvenile roost that is lower than the main roosts, horizontally separated by a few feet, and higher than my nests. This gives them a safe place to go that is not my nests and where the older ones don't beat them up.

Aart gave you some of the generic things you might consider. Without details of what you are working with I cannot get any more specific.

 

[Shalai]

I don't have any good pictures of the inside of the coop. There are 2 roost inside along with 6 nesting boxes. But, y'all have gave me an idea!

 

[Ridgerunner]

Yours free range. Excellent. Put a cage for them to sleep in built with wire so the others can see them in the coop. Allow the young ones to roam in one of those runs during the day. That way they get to see each other. By putting them in the cage in the coop at night, you train them to sleep in the coop instead of in the run.

After a week or two of "see but no touch" let them range together during the day. They will probably keep separated but not hurt each other. After a couple of weeks of them ranging together without violence try letting the young ones sleep in the coop outside of their cage. I expect you to have an easy integration.

Good luck!