I buy big bales of haylage and feed that to the ponies and the goats too - goats enjoy it, but sometimes if its strong, it tastes in the milk, and its not nice. This haylage is quite dry, which I prefer - the goats rather that than the wetter stuff.
Silage is made primarily for cows, and is usually baled a lot qucker than haylage, so is wetter and greener, andin my view not suitable for goats or horses. I would not give my goats silage.
You said it was silage, but if its small bales, then its haylage. Usually have to use the small bales within 5 days, so if you have a number of goats that would be ok. You need to be sure the bags have not any holes, as the haylage will be spoilt and unusable.
One thing - do not suddenly change from hay to haylage - mix it, and introduce gradually if you can - that will mean getting more hay obviously. Sudden change can cause tummy upsets. And usually you can reduce the amount of haylage against what you would feed hay, as it fills them up (well it does mine!)