My dogs used to stuf themselves silly when they lived at the stables, they dont go to the horses now so have that ingredient in the their diet removed.
Couple of weeks ago my bitch JRT had the same sort of thing, I too reckon she had eaten something, probably rabbit bowel or something ( I have caught her eating that before! ), she just had dry biscuits for a couple of days then came good.
They have had there wormer this morning so will see if there has been any effect by what they are eating, got 2 new springer pups coming next month so thought we better get em wormed before they arrive which is before they are due, but just in case so any evidence can be picked up and disposed of.