Definitely stop all veg and allow their systems to rebalance. they could be off veg for a few days. Don’t give them veg again until 24 hours after poops normalise, and when you do reintroduce, do it very slowly and preferably starting with herbs as they are gentler on the system. If poops don’t normalise/show any improvement after 24-48 hours of being off veg or if the poops get softer, diarrhoea etc, then they need a vet straight away.
There is a guide to probiotics below.
Also, weigh them daily while there are health concerns. This is the only way to be sure they are definitely eating enough hay.
I do need to urge you so speak to a vet though if being off veg doesn’t help within a couple of days. Too much watery poops will mean there is a risk of dehydration etc. We can only advise that the standard advice for soft poop is stop veg and that full diarrhoea is a medical emergency requiring immediate vet care, but ultimately only a vet is going to be able to tell you what is going on and whether they require some other treatment
Probiotics, Recovery Foods And Vitamin C: Overview With Product Links