ive a good working young black lab,but the last 8months hes gone very nervous,hes ok in the field,bold good worker,but inside the house,if you do a sharp movement near his head,he reels back,also when hes feeding,any noise puts him off,gunfire outside in the field no problem,i kenneled him 12 months ago,im wondering if hes,been hit during the time he was kenneled.i would be grateful,for any help.