2 weeks ago I had one of my SSH chicks become quite ill and subsequently die, I took it to the vet with symptoms such as the inability to grip with its toes and apparent paralysis in its legs, severe weight loss and runny poop with a rather bad smell to it. The vet gave it antibiotics but I think it was already too late. The vet thought it could be Mareks, the chicks temperature was fine, just seemed unable to move and sadly I'm sure the weight loss didn't happen over night, but still quick enough. This deceased chick was in with its 5 other mates all from the same hatch, they were living in my horse float so had never actually been outside on the ground or in contact with my other hens and were raised on medicated chick starter. Now 2 weeks later I have noticed that the other 5 are quite skinny, I have been told that Hamburgs aren't the plump type of chicken but since the death of the other chick i had changed the others to turkey and meat bird grower with higher protein hoping to give them a boost. And just today i noticed that one of the chicks had a very messy bottom, runny, almost liquid poop collecting on their tail feathers and a little blood staining. I'm VERY worried as these chickens are gorgeous and so super friendly and I dont want to lose another one. I plan on taking the chick with the messy bottom to a different vet, I'm a little annoyed that the first vet suggested Mareks and didn't do further tests on the first chick, but in the mean time can anyone guess what the problem could be? I am yet to worm them, at this age could worms be the problem? I also plan on treating them and their housing for lice and mites even though i haven't seen any, trying to cover all bases. They all seem to be eating and are alert and active . . . any thoughts or advice would be greatly appreciated. Will try to get an appointment with another vet asap.