Jackpot, my first hen might already be a mycoplasma carrier.

[Altairsky]

Long story short, I got my first coop and I bought my first 2 hens, already 1 year old. I didn't notice the problem at first, but now after reading online and watching pictures I think one of them might have chronic mycoplasma - which means they are both carriers.
She has no symptoms at all, she lays a lot of eggs (one every other day which is very good for this breed) and she eats like a pig. But she has this weird bubble on one side of her head, which for what I understand is caused by mycolpasma.
She's been like this for 2 months now. No other symptoms, she's very happy and active.
The other hen is perfectly fine.
What now? Does it mean that I can't add more hens to the flock or they will get sick and die?

 

[Eggcessive]

How does that nodule feel—firm or soft? I think that may be a cyst, but I could be wrong. Usually, with mycoplasma, it tends to be more around the eyelid or toward the beak. It can cause bubbles or foam in the eye, sneezing, and nasal drainage. I think if that were MG, it would have become worse, and she might have become lethargic or develop more signs. So it may not be anything to worry about.

 

[Altairsky]

The nodule is soft and movable under the skin, very similar to what a small lipoma would look like in humans.

 

[dawg53]

I agree with @Eggcessive. It's not MG. As long as your hen(s) are eating, drinking and acting like a chicken should, you have nothing to worry about.

 

[Eggcessive]

The nodule is soft and movable under the skin, very similar to what a small lipoma would look like in humans.

I would just keep a watch on it, and maybe write down the measurement. Then note if it grows, or if any other symptoms occur. Chickens have various growths just like all animals. Many are benign, and some can be cancerous.