Okay.. 6 weeks old is a chick not a hen.. and *can* make for a much different picture!
For informational purposes only and for future readers.. While my family still uses the term roo and hen in casual conversation, when discussing health or behavioral issues age truly matters.. There are chicks, pullets and cockerels until 1 year old, and hens and roosters after 1 year of age. I'm not truly sure when it changes from chick to pullet or cockerel.. but essentially figure it to be WHEN gender can be assessed. I'm always still learning!
I feel *almost* silly for asking.. but are you planning to raise and keep or harvest this bird? This is relevant to follow up suggestions and the reason why I ask, not sheer nosieness.
I know I already mentioned I'd personally not have the bird separated unless it's getting picked on or in danger. They're not meant to be alone and won't thrive too long in that manner.
It *almost* looks like an injury.. But from what I can see in the pics the blue looks more like blood vessels under the skin than bruising which is often less uniform in shape & turns yellow and green on the way back to normal. It also doesn't look actively infected.. angry and red or look like it should be hot to the touch.
Were the chicks vaccinated against anything? Sometimes vaccine sites may get a hematoma.. but I *think* that would look much more like bruising and probably not cover as large of an area and I'm just brain storming ideas.
I edited my last post to mention breast blisters which is much more obviously easier to answer the possible causes.
Admittedly partly due to MY personal life experience which *may* not be relevant here but also partly due to breed.. Ascites would still very much be on my radar of awareness, commonly called water belly as that's often how symptoms develop in older birds.. referred to as heart disease in the last post.
I do wonder if
@casportpony has any different feedback than mine, now that more information and pics have been posted? TIA!
