Chick has a large pocket of fluid around her breast area.

[Mojophanny]

Hi! I'm a new chicken parent and my blue breasted brown leghorn has a very large bubble on it's chest. This appeared yesterday but has doubled in size. They are newly being exposed to outside. They are about 2 months old. It is eating and drinking but it's poop does look more grainy than the others. At first I thought maybe tumor but it's very soft like there's liquid inside. I feel awful because I'm not sure what to do.

 

[NatJ]

Hi! I'm a new chicken parent and my blue breasted brown leghorn has a very large bubble on it's chest. This appeared yesterday but has doubled in size. They are newly being exposed to outside. They are about 2 months old. It is eating and drinking but it's poop does look more grainy than the others. At first I thought maybe tumor but it's very soft like there's liquid inside. I feel awful because I'm not sure what to do.

Could it be the crop? (Basically the stomach: it sits at the base of the neck, and ranges from empty to very full.)

If it is the crop: it will be larger at some times than others. It can feel like it contains liquid, or mushy semi-solid, or hard little grains of food, at various times. All of those are normal and healthy, as long as the chicken is acting healthy. It is common for the crop to be very full at bedtime, empty in the morning, and partly full through the day. For young chicks in a brooder with light all night, the crop may not ever be empty, but it still common for it to be extra-full in the evening.

I suggest you feel the chest of each of your other chicks. If they all have something similar, I am confident it is the crop.