I would say it is a pullet but would also like to see front views and closer it may be showing aggression to your chooks as it is at the top of the pecking order.
Tell me every one what you think the most practical chicken breed is I would go with Isa Browns as they lay plenty of and don't eat too much food.:D:thumbsup
ere is what a crow collar is: https://www.ebay.com.au/itm/Rooster-collar-SOFT-BLACK-The-Chicken-Domain-Australian-manufactured/264001080708?hash=item3d77b0cd84:m:mtQvifprskPtfNcb-zpmtOw