Why is my dog attacking my other dog?

I have 2 intact female dogs; Basset Hound and Cocker Spaniel. We bred our basset hound over 6 months ago and during her pregnancy she became aggressive about food with our cocker. When we discussed this with a professional they said it should pass once her puppies are gone and her hormones are back to normal. We didn't have any problems with her until a few weeks ago when she again became aggressive again over a few kibbles my daughter put on the floor. Then, this morning I heard growling near our back door and found our cocker sitting waiting to go out and avoiding eye contact with the Basset hound and as soon as I tried to intervene our Basset attacked. It's a lot of noise and growling, but no injuries. She is just coming out of heat. It's so surprising since our BH is so loving and playful and usually is best friends with the CS. I am wondering if we spay them both if the aggressiveness will stop, or if this is something we will need to bring a behaviorist in to correct. I am not a backyard breeder btw so no nasty comments. My BH is registered and all of the health checks were done etc. I am trying to do what is best for my dogs.