blood on the ground. not in heat?

[bv1020]

I leave my two rottweilers at my parents house while I am at work b/c I work all day. 2 days ago my dad called and said there was blood on the ground and he didn't know what it was, today I went home to pick up the dogs and there was dried blood in one of the dog bowls, a noticable amount, more than when a dog is in heat. My female is 12 months old and was in heat at nine months. also my 8 year old lab permanently lives with my parents and was there. All the dogs appear to be acting normal, what could it be and how could i find out which dog it is.

[frontierrots]

check their mouths. It sounds like they were wrestling and someone got a cut tongue, lip or gum. Could also be an ear but those are usually real obvious due the the amount of blood

[bv1020]

my dad said he checked and could not find anything, i looked today but couldn't find anything, if they vomited blood would it only be blood or would it be blood and everything else