Just to clarify, medicated feed contains an anticocidiostat, usually amprolium which acts to starve any coccidia in the gut. I'm not sure what Corbin is unless you mean Corid. I think it is more likely that this bird had a prolapse or rupture due to a reproductive malfunction (possibly salpingitis since you describe an object protruding from her vent which may well have been a "lash egg") which caused the bleeding back end, possibly helped by some pecking from her flock mates. The white diarrhoea is urates. Normally this is passed with regular faeces and is the white capping you see on poop. When it is excreted without faeces it is sometimes due to extreme heat and drinking lots but it can also be caused by a blockage of the gut preventing normal faeces from being passed and so the urates are expelled on their own. Salpingitis is an infection of the oviduct which caused egg material and pus to combine and solidify into rubbery flesh coloured masses called "lash egg" These are difficult to pass due to their irregular lumpy shape and texture and the oviduct becomes impacted with them. Sometimes a mass as large as a grapefruit develops and eventually due to the limited space in the abdominal cavity, it puts pressure on the gut and nips or constricts it to the point that the bird cannot pass faeces (just white urates), Death will usually occur within a couple of days once this happens. I'm not sure I have explained that as coherently as I might as I am well past burning the midnight oil here but hopefully you will get the gist of it.