The checklist is always locked. You copy the questions and paste them into a post here.
The vet isn't right when he says that you don't see any blood after the first dose of Baycox or any other medication. The Baycox deals with the parasite, but doesn't repair damage that is already done. Depending on the severity of the damage to the intestinal lining, you may see some reducing amounts of blood or shedding tissue for a few days. You would hope to not be seeing the fresh red blood of a severe active infection.
Have you given the first two doses two days apart? If you have I would now wait the five days. You should make sure that they are in a completely clean and dry environment. If they aren't responding quickly I wouldn't let them go and run on damp grass. They will be picking up more oocysts and increasing their parasite load. I find it best to keep them in a completely covered area where there is no chance of dew to moisten things. Keep on with the cleaning of drinkers. Make sure there is no spillage of water drinkers into the litter at all.
Did you give the Baycox directly to each bird in a single dose, or is it in the drinking water? If it's in the water, have you seen them drinking it?
You could post some pictures of their droppings and of their posture in here if you want second opinions.
Call your vet tomorrow if you have concerns, but don't give them more Baycox today if they have already been medicated. Wait the five days and watch how they go.