She may now be intolerant of the venison, which could be the reason she is refusing it and not doing well.
Once formed, IBD intolerances are generally permanent and the dog cannot go
back and eat previously eaten foods to which he/she has developed an IBD
intolerance w/o triggering a flare of IBD related inflammation.
IBD intolerances can develop to both proteins and carbs.
Exampe: Fat (eg chicken or poultry fat) corresponding to an untolerated protein (eg
chicken) should generally be avoided despite manufacturer's claims to the
contrary since quite a few IBD dogs react to even the smallest amount of
trace/residual protein in the fat or react to the fat itself.
Even meds and supps need to be carefully scrutinized for possible sources of
intolerance such as flavorings or inactive fillers such as cornstarch in
dogs not tolerating corn.
In a rescue dog with unknown dietary history, it may be prudent to avoid
ingredients commonly found in high volume supermarket or pet store dog foods
which in the US typically include beef, chicken, wheat and corn and to a
lesser extent lamb and rice.
Now is the time to up the meds/ and or add them as well (with the docs ok!) and start with a sacrifical novel protein and nothing else.
A sacrificial protein diet is used during the healing process with the expectation that the patient may become allergic to the treatment diet and will be switched to another hypoallergenic diet at the end of the diet trial. Food allergy is definitely a cause of inflammatory bowel disease.
I sent you a ton of reading. I know it's a lot to read and absorb but it's all good and important reading.
You have my info, if you have any questions.