Help......vent pecking and egg eating

Help please...just had a nasty turn

We've had one of our Black Rocks laying soft eggs which all the others dive on and eat as soon as they can. To help we have started adding the grit to the food instead of having it seperate to ensure that they are getting enough.

Just now we have had one of our Amber Stars chasing the Black Rock around the pen with an egg hanging out to finally grab it and be joined in with the others to eat it....but it didn't stop there...she then went on to keep pecking at the vent area, making it bleed and very sore...:

We've penned up the Black Rock in the corner of the pen to calm down as she really looks shook up.....anybody got any idea's about why this happened and what we can do about it???

Hi

Yes, sorry I mean't the grit/crushed shell mixture.

We got all three Black Rocks as POL's last Oct 07; we've had no egg problems with all of our other girls so they've been having enough calcium.  They get plenty of greens, mixed corn and layers pellets as well.

Maybe we just have a 'doggy' hen...

They've had a few runny poos but I thought it was because they had had too much lettuce so I've been giving them cabbages or greens that they have to work harder at.

Has she always laid soft shells or have they changed in the time you've had her?  I'm just wondering about the info Aunty found for me a few days ago about our soft shell layer ... if she's never laid a 'normal' egg then have a look here -

form here:

Quote from: "http://www.thepoultrysite.com/articles/1003/factors-influencing-shell-quality"

Diseases: Diseases like infectious bronchitis (IB), Newcastle disease (ND), avian influenza (AI) and egg drop syndrome (EDS) affect the shell quality. IB virus causes soft/rough shelled eggs, discolouration and wrinkling of the shell. EDS virus affects only the shell gland but with ND or IB, every portion of the reproductive tract can be affected.

and from here:

Quote from: "http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/205802.htm&word=egg%2cthin%2cshell"

Most “ridged,” “sunburst,” “slab-sided,” soft-shelled, or double-shelled eggs are the result of eggs colliding in the shell gland when an ovum (yolk) is released too soon after the previous one. Necropsy examinations have demonstrated that 2 full-sized eggs can be found in the shell gland pouch. As the second egg comes in contact with the first, pressure is exerted, disrupting the pattern of mineralization. The first egg acquires a white band and chalky appearance, while the second egg is flattened on its contiguous surface (ie, slab-sided). Pimpled or rough eggs may have been retained too long in the shell gland. Blood spots result when a follicle vessel along the stigma ruptures as the ovum is being released. Meat spots occur when a piece of follicle membrane or residual albumen from the previous day is incorporated into the developing egg.
Many abnormalities occur as “accidents” (no specific cause), but the incidence is much higher in hens subjected to stressful management conditions, rough handling, or vaccination during production. A significant increase in the number of soft-shelled eggs is also common as a result of viral disease such as infectious bronchitis, egg drop syndrome, and exotic Newcastle disease.
Small eggs with no yolk form around a nidus of material (residual albumen) in the magnum of the oviduct. Small eggs with reduced albumen and eggs with defective shells may be the result of damage to the epithelium of the magnum or shell gland.  
Very rarely, foreign material that enters the oviduct through the vagina (eg, a roundworm) may be incorporated into an egg.  

Goodness Peggy.  You know more about what I know than I do  :?  

Only quoting you, Aunty ... and I'm learning from the expert    

 Bad luck...hope the others all go on OK