I am a little at a loss about how you are feeding her.
Are you using the dry powder Esbilac, or the liquid stuff in the can?
If the dry, how are you mixing it? The correct ratio is 2 parts water for every 1 part formula powder (i.e., 2 tablespoons water and 1 tablespoon powder).
How much heavy cream are you adding?
How much does she weigh? We calculate the amount to feed based on the weight of the baby.
If you are diluting her formula with water over and above the ratio I mentioned, it is going to affect the amount she poops. The formula powder is a solid. They pee liquids out and poop solids; if you are diluting, there are less solids, and thus, less poop.
Just to add something else to the mix, it would be a very good idea to buy and slowly transition her to Fox Valley 20/50. It can be purchased at Henrys:
https://henryspets.com/fox-valley-da...aby-squirrels/ It has the nutrition that an older baby (over 4 weeks) like her should be eating. I would also suggest throwing a bag or two of the Henry's Healthy foods:
https://henryspets.com/diets/ - I suggest either the hazelnut or the picky bites for when she begins to wean while you are there.
We really will need a pic of the rash/bumps you mentioned. I don't know how long ago you found her but they do get ant bites and such when they are on the ground.