
If she were mine, I'd spay. Okay mate her the one time if you feel you must but to be losing like that, and for that long can't be doing her much good I'd suggest. All, bar one, of mine would 'conform', blood coloured loss through the first week, going to a pale straw colour and then either some increased slightly more coloured discharge to the end (21 days) or not much discharge at all. I had one however, who bled as usual, was mated twice, and then in the third week returned to a more significantly coloured discharge through the final week to the point I felt she'd never have taken. She had an uneventful pregnancy, and 9 puppies at the end. I only took the one litter from her - she gave me 3 worth keeping after all!
I'd not want one having a discharge for 4 weeks but they are all different. How often does she come in?