If you want to look at more detialed discussions on this, search the breeder/health forum archives.
The short of it, is that the products are not well regulated.
Testing has shown containers cultured resulting no living contents, flora that is not on the label (some possibly pathogenic), flora in differing amounts than on the label ect.
Further problems are the flora surviving digestion prior to having to compete and find a suitable place in the gut to colonize.
You may see benefits; whether they are from the probiotic, or just time, will be unknown. Consistent results are a stretch.
Good luck though,
Ian
ps, it's too late now, but the breeder is not the place to go for medical attention unless he/she is a vet.