adding chickens - pullets or layers?

[soenso]

Your silkie may go broody..and giving her eggs or chicks might be an option.
A broody can be a good way to integrate new birds.
Keep in mind tho that 50% of fertile eggs will be males, so you'll need a plan to get rid of them. Sexed chicks might work better, tho there can be errors(or deceptions) there too.

You're allowed to have 6, but do you have space for 6?
What did you end up doing for a coop and run?
https://www.backyardchickens.com/threads/prefab-options.1326539/

Integration takes extra space.

Here's some tips on.....
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.

Thanks so much for all this detailed information! I do have space for six. I ended up buying a walk-in coop from someone who was moving and couldn't take it with him. I built a run from hardware cloth. I borrowed a smaller second run made from welded wire to use during integration. I will definitely keep all this in mind going forward