Even switching to another tom, you still need more hens. I try to keep at least 4 to 5 hens for one tom.
A Blue Slate crossed with a Bronze will be either a Barred Slate (Bb Dd) or a Barred Black (Bb dd). Neither will breed true because they are not homozygous for their color genes.
Not all toms are good breeders. I eliminate rough breeders.
It would be helpful for your hen to get more hens. One tom and one hen can lead to a dead hen especially when the tom is a bad breeder.
In my experience, bad breeders don't get better at it.