Anyone experience Bluebird siblicide in their box? I have fledged many clutches but this apparent siblicide first for me. It is not wrens (HOWR) killing the chicks as I have wren guard in place. Clutch was three eggs with at least two days between eggs. Cold and rainy weather here in NJ may have contributed to spaced egg laying. I have pic with chicks, one with what appears to be head wound running circumference of head.