Weird movement in gouldian finch chick crop

[Zelda]

Hi, I'm handfeeding 2 blue gouldians, 1 split for blue and 1 parrot finch chick. They are about nine days old and was left by the parents.
For three days everything went fine but this morning I noticed that the one blue chick's crop made this weird movement and it looked as if it was vomiting a little bit.
Is it the first signs of a yeast infection?
I do have medistatin and probiotic. Can anybody please advice me what the problem is with the little one and if I must give medistatin or probiotic, how many times must I give it to them. With each feeding or only once a day.
I would really appreciate any help because I've put so much effort in, I don't want to lose any of them.
Thx.

[Sally]

How full is the crop? If the crop gets overfilled, it will come back up and look like the bird is vomiting. I've been told that when handfeeding, the crop should never be bigger than the head.

[Zelda]

Hi Sally, actually it is not that full. I've also read that and I'm trying not to give them 2 much. I'm using katee exact.

[cindy]

Was the movement sort of serpentine, wavy like a snake, S movements? If so it could be trichomonas... do you have ronex 12% or Ronivet S 12%.... you can mix this into the formula as you feed the baby and then beak does the medistatin twice a day.

Medistatin is good to use as you hand feed finch chicks...they tend to get yeasts more easily than non-handfeds. 2 x's a day

Is the crop red?