If there's no improvement after using Corid, worm your birds with Albendazole. Worms can cause blood in feces. Here's where you can order it:
https://horseprerace.com/albendazole-oral-liquid-for-horses-cattle-sheep-500ml
Please read post #5 in this link:
https://www.backyardchickens.com/threads/weight-question-with-dewormer-and-how-long-to-treat—-site-won’t-load-previous-forums-for-me.1664386/#post-28609598
Endocox aka Toltrazuril is more in line for treating severe cases of the protozoa that causes blood in feces or when Corid is ineffective.
Corid is not an antibiotic, it is a Thiamine blocker.
It's best to start with the Corid unless you're seeing blood in feces.
You saw roundworms in feces...
As mentioned by @Eggcessive, Tiagard only treats Mycoplasma Gallisepticum (MG.) MG is very contagious and easily spreads to other birds.
You stated that you recently cleaned their coop and run. Did you use certain detergents or chemicals to clean the coop to cause a reaction with your rooster...
I agree with @Wyorp Rock. Change 2: Go ahead and start the Safeguard and the Equimax at the same time. Dose the rest of your birds with the Safeguard only since they arnt showing tapeworm segments in feces.
Just for your info; blood in feces can be caused by worms.
Your vet is correct, it's not bumblefoot. It's footpad dermatitis. Here's an article on how to treat it:
https://www.backyardchickens.com/articles/early-stages-of-contact-dermatitis-foot-pad-dermatitis.78413/
It takes time for leg injuries to heal depending on the severity. If you've ever sprained an ankle, it also takes time to heal depending on the severity.