Yes, union workers can be legally fired for going on strike, but there are laws that protect their right to strike under certain conditions.
It is an action taken by union workers without the union leadership authorisation, support or approval
Picket Line
A+...meat workers union
That would be determined by the Rules and bylaws of the Union. But, if its an authorized strike, called by the Union (not an unauthorized "wildcat" strike by workers without Union sanction), then the Union is not going to be too happy with scabs who did not stand with them.
A union strike is when union members (workers) stop working and often protest outside the building while the union leaders bargain collectively with the employer.
Strike while the iron is hot! The union workers are on strike for better wages.
Picket line, to visibly inform the public that the union is on strike, and to invite other workers not to cross the linbe to work or deliver goods.
Picket line
BOYCOTT. K.Harris
"On strike" means they do not go to work in protest of something they think is unfair.
Factory owners by union workers
Yes, any group of employees with the exception of employees under the Taylor Law (civil service employees ie. police, fire, etc.)You can strike, but it would just be missing work and you can be fired.If you have a union, you can still be fired for going on strike. Example (NWA Aircraft Mechanics)