Behaviour of foster dog - advice needed please

[terrier141]

I am an experienced fosterer for a small animal rescue and have fostered 27 dogs (also have 2 of my own).
Currently i have an amazing Springer in foster with me but her behaviour has changed dramatically over the last few days.
I should add that she is currently on day 9 of a season (was already on day 5 when i collected her from the pound).
She is perfect in every way - but the last 2 days she has started attacking the other 3 dogs here.
Now i am unable to complete a fair assessment of her behaviour until she is out of season and hormones have had chance to settle as i cant determine whether this is her true personality or down to raging hormones???
She was great with the other dogs initially.
I have only ever had 2 other dogs in season and never experienced any "grumpy" behaviour from those. I do remember a vet telling me that bitches can get very grumpy when in season and act completely out of character.
Anyone else had experience of this? i am keeping her separate from the others as much as possible - they are never left unsupervised.
She will not be available for adoption til she has been spayed and undergone a proper assessment - which looks likely to take some time anyway - but would appreciate any advice. thanks x