I'm not sure, every flock and bird is different. .. for u it may be worse than other people since you are adding silkies which are not just younger but silkies can't see as well and the others may make fun of them besides pecking order. I would recommend not adding them but it's your choice if you want problems in your flock.
Your numbers in your post and signature don’t quite add up but that’s OK. I believe you have either 2 or 3 six-week-old Silkies. In either case it is not a lot but at least it is not one. One could be a lot rougher.
I’m not a big believer that size makes a difference. After all, bantams often dominate full sized fowl. The big factor for you is maturity. Your 11-week-olds are much more mature than your young Silkies and will greatly outrank them in the pecking order until they are all mature. That would still be true if the breeds were reversed. That may or may not be an issue. You are dealing with behaviors of living animals, anything can happen. You don’t get guarantees one way or another.
Right now I have 20-week-old and 13-week-old brooder raised chicks and 7-week-old broody raised chicks living together with my adult flock. I have another broody hen hatching right now. She will raise them with the flock. It’s all pretty peaceful but that does not mean everything will go great for you. There are a lot of factors involved.
First I have a lot of room. The different-aged chickens can form their own sub-flocks during the day and avoid the more mature older ones if they wish. They kind of keep separate but not all that much. The 13 and 20’s intermingle a fair amount. The 7-week-olds, not so much. One of the ways chickens have learned to live together in a flock is, when there is conflict, the weaker runs away from the stronger. They need the room to run. I have no idea how much room you have.
More mature chickens rank higher in the pecking order and are often not shy about enforcing that rank, often by pecking any less-mature chicken that enters its personal space. Some will seek out weaker chickens to injure them. Mine are normally not that brutal but some can be. You can find plenty of stories about that on this forum. That’s one of your risk factors, you may be unlucky enough to have one that is a brute. Again room is very important so the less-mature can get away and avoid, but also you need to set up separate feeding and watering stations so the weaker can eat and drink without challenging the older ones.
I find that immature chickens are often more vicious than fully mature chickens. Not always, like everything else not always, but I have noticed a trend. Your 10 week olds are just about pre-teens, not quite adolescents. I think your risk factor is a bit higher since you don’t have full adults, but as you can see by the ages of mine that is not always a huge problem. It’s just something to be aware of.
Another factor is that mine were all raised in the flock. My brooder is in the coop. My broody hens raise them with the flock. They are all together as soon as they hatch. Some chickens, not all and surprisingly usually a hen instead of a rooster as long as the invaders are chicks or older pullets, will be defensive and protect their territory from invading chickens. By raising mine with the flock I avoid all that drama. I suspect your Silkies have not been raised with the flock. If you can at all I strongly recommend you house your Silkies next to your older chicks across wire for at least a week before you let them mingle. Longer might not be a bad idea.
I suggest you do a search on Azygous and look at the links in her signature. The one I’m thinking of is the one about a safe haven. I don’t do that, but especially if your space it tight, a safe haven can make a lot of difference in your success. Another way to stretch space is to provide places for the chicks to hide from the older ones. If they can get out of line-of-sight they are less likely to get picked on.
Is your integration doomed to failure? Not at all, people do it successfully all the time but sometimes there are disasters. I suggest you house them side by side for at least a week, provide as much space as you can as well as separate feeding and watering places, and let them mingle the first time when you can be around to watch. I do not suggest you first let them mingle by locking them in the coop together at night and wake up together unless you will be down there by daybreak to observe when they wake up. Give then as much room as you can. Sometimes these things go so smoothly you wonder what all the fuss was about, sometimes they end in disaster. I can’t emphasize enough how important room is, but most of the time I’d expect a bit of drama then your Silkies will form a sub-flock and avoid the older until the Silkies fully mature. But I do expect some drama.