testing is always a good idea, but try grabbing 3 samples over a few days so you have the option of the TF test as well as standard one.
I keep a food diary for my girl - everything that goes in is logged inc time - and everything that comes out
is described and logged too.
This helps me figure what has set my girls belly off as can happen from time to time.
From my logs all her healthy poops were dark and dry and formed... obvious.
But from my observations I found that the lighter in colour (from dark brown upto light yellow) her poops are the more unsettled my girls belly is and smellier her poops.
Ive even seen when she has passed a movement that was 3/4 dry formed dark and healthy sausage shape but followed by an unexpected wet yellow runny 1/4 at the end.
She basically had a healthy poo and unhealthy poo together in same visit to her tray.
I was able to check my diary to identify the food/treat (think it was applaws) that she had eaten after and on top of her usual meals and note that it gave her this reaction.
Get samples (x3) and see if she improves over the few days you are gathering samples... It might have been something she found and ate without you knowing?...
I recommend starting a food diary and keeping it religiously for many weeks. it can become a great tool for learning what Daisy can and cant tolerate.
Sometimes it could be a regular treat she doesnt normally react to, but given in slightly to much quantity. For eg. My girl can eat 1/2 tin of applaws (white fish) or 1/2 sachet of Felix (tasty, but junk food IMO so I give only as treat) with no problem... but everytime she has eaten a whole tin/sachet of applaws or felix she has had soft, smelly, light brown poops on her next tray visit.